David Fivenson, MD

To the Editor:

Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with human herpesvirus 8 (HHV-8) infection.¹ There are 4 main recognized epidemiologic forms of KS: classic, endemic, epidemic, and iatrogenic (Table). Nonepidemic KS is a recently described rare fifth type of KS that occurs in a subset of patients who do not fit the other classifications—HIV-negative patients without detectable cellular or humoral immune deficiency. This subset has been described as clinically similar to classic KS with limited disease but occurring in younger men.^2,3 We describe a case of nonepidemic KS in a Middle Eastern heterosexual immunocompetent man.

A 30-year-old man presented for evaluation of a growth on the nose of 3 months’ duration. The patient reported being otherwise healthy and was not taking long-term medications. He denied a history of malignancy, organ transplant, or immunosuppressive therapy. He was born in Syria and lived in Thailand for several years prior to moving to the United States. HIV testing 6 months prior to presentation was negative. He denied fever, chills, lymphadenopathy, shortness of breath, hemoptysis, melena, hematochezia, and intravenous drug use.

Physical examination revealed a solitary shiny, 7-mm, pink-red papule on the nasal dorsum (Figure 1). No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. A laboratory workup consisting of serum immunoglobulins and serum protein electrophoresis was unremarkable. Tests for HIV-1 and HIV-2 as well as human T-lymphotropic virus 1 and 2 were negative. The CD4 and CD8 counts were within reference range. Histopathology of a shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles and admixed with plasma cells and occasional mitotic figures. Immunohistochemistry showed that the spindle cells stained positive for CD34, CD31, and HHV-8 (Figure 2). The lesion resolved after treatment with cryotherapy. Repeat HIV testing 3 months later was negative. No recurrence or new lesions were identified at 3-month follow-up.

Similar to the other subtypes of KS, the nonepidemic form is dependent on HHV-8 infection, which is more commonly transmitted via saliva and sexual contact.^3,4 After infecting endothelial cells, HHV-8 is believed to activate the mammalian target of rapamycin and nuclear factor κB pathways, resulting in aberrant cellular differentiation and neoangiogenesis through upregulation of vascular endothelial growth factor and basic fibroblast growth factor.^2,4 Similar to what is seen with other herpesviruses, HHV-8 infection typically is lifelong due to the virus’s ability to establish latency within human B cells and endothelial cells as well as undergo sporadic bouts of lytic reactivation during its life cycle.⁴

Nonepidemic KS resembles other variants clinically, manifesting as erythematous or violaceous, painless, nonblanchable macules, papules, and nodules.¹ Early lesions often are asymptomatic and can manifest as pigmented macules or small papules that vary from pale pink to vivid purple. Nodules also can occur and be exophytic and ulcerated with bleeding.¹ Secondary lymphoproliferative disorders including Castleman disease and lymphoma have been reported.^2,5

In contrast to other types of KS in which pulmonary or gastrointestinal tract lesions can develop with hemoptysis or hematochezia, mucocutaneous and visceral lesions rarely are reported in nonepidemic KS.³ Lymphedema, a feature associated with endemic KS, is notably absent in nonepidemic KS.^1,3

The differential diagnosis applicable to all KS subtypes includes other vascular lesions such as angiomatosis and angiosarcoma. Histopathologic analysis is critical to differentiate KS from these conditions; visual diagnosis alone has only an 80% positive predictive value for KS.⁴ The histopathologic presentation of KS is a vascular proliferation in the dermis accompanied by an increased number of vessels without an endothelial cell lining.⁴ Spindle cell proliferation also is a common feature and is considered to be the KS tumor cell. Immunostaining for HHV-8 antigen as well as for CD31 and CD34 can be used to confirm the diagnosis.⁴

The management and prognosis of KS depends on the epidemiologic subtype. Classic and nonepidemic KS generally are indolent with a good prognosis. Periodic follow-up is recommended because of an increased risk for secondary malignancy such as lymphoma. The treatment of epidemic KS is highly active antiretroviral therapy. Similarly, reduction of immunosuppression is warranted for iatrogenic KS. For all types, cutaneous lesions can be treated with local excision, cryosurgery, radiation, chemotherapy, intralesional vincristine, or a topical agent such as imiquimod or alitretinoin.⁶

To the Editor:

Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with human herpesvirus 8 (HHV-8) infection.¹ There are 4 main recognized epidemiologic forms of KS: classic, endemic, epidemic, and iatrogenic (Table). Nonepidemic KS is a recently described rare fifth type of KS that occurs in a subset of patients who do not fit the other classifications—HIV-negative patients without detectable cellular or humoral immune deficiency. This subset has been described as clinically similar to classic KS with limited disease but occurring in younger men.^2,3 We describe a case of nonepidemic KS in a Middle Eastern heterosexual immunocompetent man.

A 30-year-old man presented for evaluation of a growth on the nose of 3 months’ duration. The patient reported being otherwise healthy and was not taking long-term medications. He denied a history of malignancy, organ transplant, or immunosuppressive therapy. He was born in Syria and lived in Thailand for several years prior to moving to the United States. HIV testing 6 months prior to presentation was negative. He denied fever, chills, lymphadenopathy, shortness of breath, hemoptysis, melena, hematochezia, and intravenous drug use.

Physical examination revealed a solitary shiny, 7-mm, pink-red papule on the nasal dorsum (Figure 1). No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. A laboratory workup consisting of serum immunoglobulins and serum protein electrophoresis was unremarkable. Tests for HIV-1 and HIV-2 as well as human T-lymphotropic virus 1 and 2 were negative. The CD4 and CD8 counts were within reference range. Histopathology of a shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles and admixed with plasma cells and occasional mitotic figures. Immunohistochemistry showed that the spindle cells stained positive for CD34, CD31, and HHV-8 (Figure 2). The lesion resolved after treatment with cryotherapy. Repeat HIV testing 3 months later was negative. No recurrence or new lesions were identified at 3-month follow-up.

Similar to the other subtypes of KS, the nonepidemic form is dependent on HHV-8 infection, which is more commonly transmitted via saliva and sexual contact.^3,4 After infecting endothelial cells, HHV-8 is believed to activate the mammalian target of rapamycin and nuclear factor κB pathways, resulting in aberrant cellular differentiation and neoangiogenesis through upregulation of vascular endothelial growth factor and basic fibroblast growth factor.^2,4 Similar to what is seen with other herpesviruses, HHV-8 infection typically is lifelong due to the virus’s ability to establish latency within human B cells and endothelial cells as well as undergo sporadic bouts of lytic reactivation during its life cycle.⁴

Nonepidemic KS resembles other variants clinically, manifesting as erythematous or violaceous, painless, nonblanchable macules, papules, and nodules.¹ Early lesions often are asymptomatic and can manifest as pigmented macules or small papules that vary from pale pink to vivid purple. Nodules also can occur and be exophytic and ulcerated with bleeding.¹ Secondary lymphoproliferative disorders including Castleman disease and lymphoma have been reported.^2,5

In contrast to other types of KS in which pulmonary or gastrointestinal tract lesions can develop with hemoptysis or hematochezia, mucocutaneous and visceral lesions rarely are reported in nonepidemic KS.³ Lymphedema, a feature associated with endemic KS, is notably absent in nonepidemic KS.^1,3

The differential diagnosis applicable to all KS subtypes includes other vascular lesions such as angiomatosis and angiosarcoma. Histopathologic analysis is critical to differentiate KS from these conditions; visual diagnosis alone has only an 80% positive predictive value for KS.⁴ The histopathologic presentation of KS is a vascular proliferation in the dermis accompanied by an increased number of vessels without an endothelial cell lining.⁴ Spindle cell proliferation also is a common feature and is considered to be the KS tumor cell. Immunostaining for HHV-8 antigen as well as for CD31 and CD34 can be used to confirm the diagnosis.⁴

The management and prognosis of KS depends on the epidemiologic subtype. Classic and nonepidemic KS generally are indolent with a good prognosis. Periodic follow-up is recommended because of an increased risk for secondary malignancy such as lymphoma. The treatment of epidemic KS is highly active antiretroviral therapy. Similarly, reduction of immunosuppression is warranted for iatrogenic KS. For all types, cutaneous lesions can be treated with local excision, cryosurgery, radiation, chemotherapy, intralesional vincristine, or a topical agent such as imiquimod or alitretinoin.⁶

To the Editor:

Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with human herpesvirus 8 (HHV-8) infection.¹ There are 4 main recognized epidemiologic forms of KS: classic, endemic, epidemic, and iatrogenic (Table). Nonepidemic KS is a recently described rare fifth type of KS that occurs in a subset of patients who do not fit the other classifications—HIV-negative patients without detectable cellular or humoral immune deficiency. This subset has been described as clinically similar to classic KS with limited disease but occurring in younger men.^2,3 We describe a case of nonepidemic KS in a Middle Eastern heterosexual immunocompetent man.

A 30-year-old man presented for evaluation of a growth on the nose of 3 months’ duration. The patient reported being otherwise healthy and was not taking long-term medications. He denied a history of malignancy, organ transplant, or immunosuppressive therapy. He was born in Syria and lived in Thailand for several years prior to moving to the United States. HIV testing 6 months prior to presentation was negative. He denied fever, chills, lymphadenopathy, shortness of breath, hemoptysis, melena, hematochezia, and intravenous drug use.

Physical examination revealed a solitary shiny, 7-mm, pink-red papule on the nasal dorsum (Figure 1). No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. A laboratory workup consisting of serum immunoglobulins and serum protein electrophoresis was unremarkable. Tests for HIV-1 and HIV-2 as well as human T-lymphotropic virus 1 and 2 were negative. The CD4 and CD8 counts were within reference range. Histopathology of a shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles and admixed with plasma cells and occasional mitotic figures. Immunohistochemistry showed that the spindle cells stained positive for CD34, CD31, and HHV-8 (Figure 2). The lesion resolved after treatment with cryotherapy. Repeat HIV testing 3 months later was negative. No recurrence or new lesions were identified at 3-month follow-up.

Similar to the other subtypes of KS, the nonepidemic form is dependent on HHV-8 infection, which is more commonly transmitted via saliva and sexual contact.^3,4 After infecting endothelial cells, HHV-8 is believed to activate the mammalian target of rapamycin and nuclear factor κB pathways, resulting in aberrant cellular differentiation and neoangiogenesis through upregulation of vascular endothelial growth factor and basic fibroblast growth factor.^2,4 Similar to what is seen with other herpesviruses, HHV-8 infection typically is lifelong due to the virus’s ability to establish latency within human B cells and endothelial cells as well as undergo sporadic bouts of lytic reactivation during its life cycle.⁴

Nonepidemic KS resembles other variants clinically, manifesting as erythematous or violaceous, painless, nonblanchable macules, papules, and nodules.¹ Early lesions often are asymptomatic and can manifest as pigmented macules or small papules that vary from pale pink to vivid purple. Nodules also can occur and be exophytic and ulcerated with bleeding.¹ Secondary lymphoproliferative disorders including Castleman disease and lymphoma have been reported.^2,5

In contrast to other types of KS in which pulmonary or gastrointestinal tract lesions can develop with hemoptysis or hematochezia, mucocutaneous and visceral lesions rarely are reported in nonepidemic KS.³ Lymphedema, a feature associated with endemic KS, is notably absent in nonepidemic KS.^1,3

The differential diagnosis applicable to all KS subtypes includes other vascular lesions such as angiomatosis and angiosarcoma. Histopathologic analysis is critical to differentiate KS from these conditions; visual diagnosis alone has only an 80% positive predictive value for KS.⁴ The histopathologic presentation of KS is a vascular proliferation in the dermis accompanied by an increased number of vessels without an endothelial cell lining.⁴ Spindle cell proliferation also is a common feature and is considered to be the KS tumor cell. Immunostaining for HHV-8 antigen as well as for CD31 and CD34 can be used to confirm the diagnosis.⁴

The management and prognosis of KS depends on the epidemiologic subtype. Classic and nonepidemic KS generally are indolent with a good prognosis. Periodic follow-up is recommended because of an increased risk for secondary malignancy such as lymphoma. The treatment of epidemic KS is highly active antiretroviral therapy. Similarly, reduction of immunosuppression is warranted for iatrogenic KS. For all types, cutaneous lesions can be treated with local excision, cryosurgery, radiation, chemotherapy, intralesional vincristine, or a topical agent such as imiquimod or alitretinoin.⁶

Adult T-cell leukemia/lymphoma (ATLL) is an uncommon neoplasm of mature T lymphocytes associated with infection by human T-lymphotropic virus 1 (HTLV-1),^1-3 which is increasing in incidence in areas of the United States with large immigrant populations.⁴ Human T-lymphotrophic virus 1 infection is asymptomatic in most patients and has been associated with ATLL as well as tropical spastic paraparesis.⁵ We present a case of rapid-onset ATLL in an 82-year-old Japanese man who had immigrated to the United States.

Case Report

An 82-year-old Japanese man who had immigrated to the United States presented with papules and nodules on the neck, trunk, and arms of 4 weeks’ duration. Minimal pruritus was associated with the lesions, which were otherwise asymptomatic. The patient reported that he was generally healthy, and a review of systems was negative.

Physical examination revealed numerous erythematous and violaceous papules and nodules on the right side of the neck (Figure 1A), chest, back, abdomen, groin, left arm (Figure 1B), and medial thighs. Bilateral axillary and inguinal lymphadenopathy also was noted.

A biopsy from the abdomen revealed a dense, atypical, pandermal lymphoid infiltrate comprised of medium-sized lymphocytes with oval nuclei, fine chromatin, and pale cytoplasm (Figure 2). Mitotic figures and apoptotic cells also were observed. Immunostaining was strongly and diffusely positive for CD4 (Figure 3A), B-cell lymphoma 2 (Bcl-2)(Figure 3B), CD3, and programmed death 1, and was negative for CD8, CD10, CD20, CD30, and myeloperoxidase.

A bone marrow biopsy revealed an atypical T-cell population on flow cytometry. Western blot analysis for HTLV-1 antibodies was positive. Complete blood cell count and complete metabolic panel were within reference range.

Clinical and histopathologic findings fit the diagnosis of ATLL. The patient was referred to hematology/oncology, but the rapid progression of lesions continued, and the patient died within 4 months of initial presentation.

Comment

Etiology
First described in 1977, ATLL is an uncommon neoplasm of mature T cells.⁶ The etiology is associated with infection by the retrovirus HTLV-1, which is endemic in Southern Japan, the Caribbean, Central and West Africa, and Central and South America, with increasing incidence in areas of the United States with large immigrant populations.⁷ The incidence of ATLL among all registered lymphoma cases from 2003 to 2008 in Japan was 8.3% compared to 0.2% in the United States.⁷

Transmission of HTLV-1
Human T-lymphotropic virus 1 is a retrovirus most commonly found in CD4⁺T cells and can be transmitted through breast milk, sexual intercourse, and blood exposure (eg, blood transfusion), with breastfeeding and blood exposure being the most common.^8-10 Human T-lymphotrophic virus 1 has been described as the causative agent for 3 entities: (1) ATLL, (2) a nervous system degenerative disorder known as HTLV-1–associated myelopathy or tropical spastic paraparesis, and (3) HTLV-1 uveitis.^5,11 It is thought that 10 to 20 million individuals worldwide are infected with HTLV-1.¹²

The evolution from infection with HTLV-1 to ATLL is thought to involve multiple steps.^13,14 Those who contract the virus later in life rarely, if ever, develop ATLL, suggesting that this progression requires considerable time to evolve to carcinogenesis. More than 90% of those infected with HTLV-1 remain asymptomatic, while only 2% to 3% of women and 6% to 7% of men develop ATLL with a median incubation period greater than 15 to 20 years.⁷

Subtypes
Adult T-cell leukemia/lymphoma has been divided into 4 clinical subtypes based on clinical presentation and prognosis.¹⁵ The acute type is more aggressive and has a poorer prognosis, while the chronic and smoldering types have a more indolent course. The smoldering variant largely has only cutaneous involvement with less than 1% of the peripheral leukocytes being atypical lymphocytes.¹⁶ A cutaneous subtype in which few to no leukemic cells are present also has been described and may overlap with the smoldering variant.The cutaneous variant has been further classified into 2 subtypes, tumoral and erythematopapular, with the tumoral subtype carrying a worse prognosis.^17,18 Clinically, 39% to 57% of ATLL cases have skin involvement, with nearly one-third reporting skin manifestations as the first symptom.^19,20 The cutaneous manifestations vary greatly and may include papules, plaques, nodules, tumors, erythematous patches, or erythroderma.^4,21 In addition to skin manifestations, most patients with acute ATLL demonstrate leukemia, lymphadenopathy, organomegaly, and hypercalcemia.²²

Histopathology
Histologically, both the smoldering and chronic forms of tumoral or erythematopapular ATLL demonstrate a cutaneous, dermal, or subcutaneous infiltrate of small- to medium-sized CD4⁺ T cells with histiocytes and admixed granulomas.⁴ Epidermotropism and Pautrier microabscesses often are limited or absent but can be seen. The neoplastic T cells involved in ATLL commonly express CD3, CD4, CD25, CD30, and programmed death 1, and T-cell clonality frequently is present.^11,22 Even with staining, diagnosis of ATLL is difficult, as it requires positive testing for HTLV-1 antibody as well as monoclonal integration of HTLV-1 proviral DNA into tumor cells.¹¹ Clinical information is vital in coming to this diagnosis, as there is such great histopathologic overlap with other cutaneous T-cell lymphomas.²³

Differential Diagnosis
The differential diagnosis includes other small- or medium-sized T-cell lymphomas. The chronic and smoldering types can be difficult to distinguish from mycosis fungoides. Primary cutaneous CD4⁺ small- or medium-sized pleomorphic T-cell lymphoma also must be considered, though it often is confined to the skin and can be differentiated from ATLL, as systemic involvement is commonly present in the latter.

Treatment
Treatment decisions should be made based on the subclassification and prognostic factors at the time of diagnosis. High doses of interferon alfa and zidovudine may show some benefit, but many cases require multiagent chemotherapy.²² The only possible curative treatment is allogeneic stem cell transplant. Mogamulizumab, an antichemokine receptor 4 monoclonal antibody, has demonstrated some ATLL antitumor activity.²⁴

Adult T-cell leukemia/lymphoma (ATLL) is an uncommon neoplasm of mature T lymphocytes associated with infection by human T-lymphotropic virus 1 (HTLV-1),^1-3 which is increasing in incidence in areas of the United States with large immigrant populations.⁴ Human T-lymphotrophic virus 1 infection is asymptomatic in most patients and has been associated with ATLL as well as tropical spastic paraparesis.⁵ We present a case of rapid-onset ATLL in an 82-year-old Japanese man who had immigrated to the United States.

Case Report

An 82-year-old Japanese man who had immigrated to the United States presented with papules and nodules on the neck, trunk, and arms of 4 weeks’ duration. Minimal pruritus was associated with the lesions, which were otherwise asymptomatic. The patient reported that he was generally healthy, and a review of systems was negative.

Physical examination revealed numerous erythematous and violaceous papules and nodules on the right side of the neck (Figure 1A), chest, back, abdomen, groin, left arm (Figure 1B), and medial thighs. Bilateral axillary and inguinal lymphadenopathy also was noted.

A biopsy from the abdomen revealed a dense, atypical, pandermal lymphoid infiltrate comprised of medium-sized lymphocytes with oval nuclei, fine chromatin, and pale cytoplasm (Figure 2). Mitotic figures and apoptotic cells also were observed. Immunostaining was strongly and diffusely positive for CD4 (Figure 3A), B-cell lymphoma 2 (Bcl-2)(Figure 3B), CD3, and programmed death 1, and was negative for CD8, CD10, CD20, CD30, and myeloperoxidase.

A bone marrow biopsy revealed an atypical T-cell population on flow cytometry. Western blot analysis for HTLV-1 antibodies was positive. Complete blood cell count and complete metabolic panel were within reference range.

Clinical and histopathologic findings fit the diagnosis of ATLL. The patient was referred to hematology/oncology, but the rapid progression of lesions continued, and the patient died within 4 months of initial presentation.

Comment

Etiology
First described in 1977, ATLL is an uncommon neoplasm of mature T cells.⁶ The etiology is associated with infection by the retrovirus HTLV-1, which is endemic in Southern Japan, the Caribbean, Central and West Africa, and Central and South America, with increasing incidence in areas of the United States with large immigrant populations.⁷ The incidence of ATLL among all registered lymphoma cases from 2003 to 2008 in Japan was 8.3% compared to 0.2% in the United States.⁷

Transmission of HTLV-1
Human T-lymphotropic virus 1 is a retrovirus most commonly found in CD4⁺T cells and can be transmitted through breast milk, sexual intercourse, and blood exposure (eg, blood transfusion), with breastfeeding and blood exposure being the most common.^8-10 Human T-lymphotrophic virus 1 has been described as the causative agent for 3 entities: (1) ATLL, (2) a nervous system degenerative disorder known as HTLV-1–associated myelopathy or tropical spastic paraparesis, and (3) HTLV-1 uveitis.^5,11 It is thought that 10 to 20 million individuals worldwide are infected with HTLV-1.¹²

The evolution from infection with HTLV-1 to ATLL is thought to involve multiple steps.^13,14 Those who contract the virus later in life rarely, if ever, develop ATLL, suggesting that this progression requires considerable time to evolve to carcinogenesis. More than 90% of those infected with HTLV-1 remain asymptomatic, while only 2% to 3% of women and 6% to 7% of men develop ATLL with a median incubation period greater than 15 to 20 years.⁷

Subtypes
Adult T-cell leukemia/lymphoma has been divided into 4 clinical subtypes based on clinical presentation and prognosis.¹⁵ The acute type is more aggressive and has a poorer prognosis, while the chronic and smoldering types have a more indolent course. The smoldering variant largely has only cutaneous involvement with less than 1% of the peripheral leukocytes being atypical lymphocytes.¹⁶ A cutaneous subtype in which few to no leukemic cells are present also has been described and may overlap with the smoldering variant.The cutaneous variant has been further classified into 2 subtypes, tumoral and erythematopapular, with the tumoral subtype carrying a worse prognosis.^17,18 Clinically, 39% to 57% of ATLL cases have skin involvement, with nearly one-third reporting skin manifestations as the first symptom.^19,20 The cutaneous manifestations vary greatly and may include papules, plaques, nodules, tumors, erythematous patches, or erythroderma.^4,21 In addition to skin manifestations, most patients with acute ATLL demonstrate leukemia, lymphadenopathy, organomegaly, and hypercalcemia.²²

Histopathology
Histologically, both the smoldering and chronic forms of tumoral or erythematopapular ATLL demonstrate a cutaneous, dermal, or subcutaneous infiltrate of small- to medium-sized CD4⁺ T cells with histiocytes and admixed granulomas.⁴ Epidermotropism and Pautrier microabscesses often are limited or absent but can be seen. The neoplastic T cells involved in ATLL commonly express CD3, CD4, CD25, CD30, and programmed death 1, and T-cell clonality frequently is present.^11,22 Even with staining, diagnosis of ATLL is difficult, as it requires positive testing for HTLV-1 antibody as well as monoclonal integration of HTLV-1 proviral DNA into tumor cells.¹¹ Clinical information is vital in coming to this diagnosis, as there is such great histopathologic overlap with other cutaneous T-cell lymphomas.²³

Differential Diagnosis
The differential diagnosis includes other small- or medium-sized T-cell lymphomas. The chronic and smoldering types can be difficult to distinguish from mycosis fungoides. Primary cutaneous CD4⁺ small- or medium-sized pleomorphic T-cell lymphoma also must be considered, though it often is confined to the skin and can be differentiated from ATLL, as systemic involvement is commonly present in the latter.

Treatment
Treatment decisions should be made based on the subclassification and prognostic factors at the time of diagnosis. High doses of interferon alfa and zidovudine may show some benefit, but many cases require multiagent chemotherapy.²² The only possible curative treatment is allogeneic stem cell transplant. Mogamulizumab, an antichemokine receptor 4 monoclonal antibody, has demonstrated some ATLL antitumor activity.²⁴

Adult T-cell leukemia/lymphoma (ATLL) is an uncommon neoplasm of mature T lymphocytes associated with infection by human T-lymphotropic virus 1 (HTLV-1),^1-3 which is increasing in incidence in areas of the United States with large immigrant populations.⁴ Human T-lymphotrophic virus 1 infection is asymptomatic in most patients and has been associated with ATLL as well as tropical spastic paraparesis.⁵ We present a case of rapid-onset ATLL in an 82-year-old Japanese man who had immigrated to the United States.

Case Report

An 82-year-old Japanese man who had immigrated to the United States presented with papules and nodules on the neck, trunk, and arms of 4 weeks’ duration. Minimal pruritus was associated with the lesions, which were otherwise asymptomatic. The patient reported that he was generally healthy, and a review of systems was negative.

Physical examination revealed numerous erythematous and violaceous papules and nodules on the right side of the neck (Figure 1A), chest, back, abdomen, groin, left arm (Figure 1B), and medial thighs. Bilateral axillary and inguinal lymphadenopathy also was noted.

A biopsy from the abdomen revealed a dense, atypical, pandermal lymphoid infiltrate comprised of medium-sized lymphocytes with oval nuclei, fine chromatin, and pale cytoplasm (Figure 2). Mitotic figures and apoptotic cells also were observed. Immunostaining was strongly and diffusely positive for CD4 (Figure 3A), B-cell lymphoma 2 (Bcl-2)(Figure 3B), CD3, and programmed death 1, and was negative for CD8, CD10, CD20, CD30, and myeloperoxidase.

A bone marrow biopsy revealed an atypical T-cell population on flow cytometry. Western blot analysis for HTLV-1 antibodies was positive. Complete blood cell count and complete metabolic panel were within reference range.

Clinical and histopathologic findings fit the diagnosis of ATLL. The patient was referred to hematology/oncology, but the rapid progression of lesions continued, and the patient died within 4 months of initial presentation.

Comment

Etiology
First described in 1977, ATLL is an uncommon neoplasm of mature T cells.⁶ The etiology is associated with infection by the retrovirus HTLV-1, which is endemic in Southern Japan, the Caribbean, Central and West Africa, and Central and South America, with increasing incidence in areas of the United States with large immigrant populations.⁷ The incidence of ATLL among all registered lymphoma cases from 2003 to 2008 in Japan was 8.3% compared to 0.2% in the United States.⁷

Transmission of HTLV-1
Human T-lymphotropic virus 1 is a retrovirus most commonly found in CD4⁺T cells and can be transmitted through breast milk, sexual intercourse, and blood exposure (eg, blood transfusion), with breastfeeding and blood exposure being the most common.^8-10 Human T-lymphotrophic virus 1 has been described as the causative agent for 3 entities: (1) ATLL, (2) a nervous system degenerative disorder known as HTLV-1–associated myelopathy or tropical spastic paraparesis, and (3) HTLV-1 uveitis.^5,11 It is thought that 10 to 20 million individuals worldwide are infected with HTLV-1.¹²

The evolution from infection with HTLV-1 to ATLL is thought to involve multiple steps.^13,14 Those who contract the virus later in life rarely, if ever, develop ATLL, suggesting that this progression requires considerable time to evolve to carcinogenesis. More than 90% of those infected with HTLV-1 remain asymptomatic, while only 2% to 3% of women and 6% to 7% of men develop ATLL with a median incubation period greater than 15 to 20 years.⁷

Subtypes
Adult T-cell leukemia/lymphoma has been divided into 4 clinical subtypes based on clinical presentation and prognosis.¹⁵ The acute type is more aggressive and has a poorer prognosis, while the chronic and smoldering types have a more indolent course. The smoldering variant largely has only cutaneous involvement with less than 1% of the peripheral leukocytes being atypical lymphocytes.¹⁶ A cutaneous subtype in which few to no leukemic cells are present also has been described and may overlap with the smoldering variant.The cutaneous variant has been further classified into 2 subtypes, tumoral and erythematopapular, with the tumoral subtype carrying a worse prognosis.^17,18 Clinically, 39% to 57% of ATLL cases have skin involvement, with nearly one-third reporting skin manifestations as the first symptom.^19,20 The cutaneous manifestations vary greatly and may include papules, plaques, nodules, tumors, erythematous patches, or erythroderma.^4,21 In addition to skin manifestations, most patients with acute ATLL demonstrate leukemia, lymphadenopathy, organomegaly, and hypercalcemia.²²

Histopathology
Histologically, both the smoldering and chronic forms of tumoral or erythematopapular ATLL demonstrate a cutaneous, dermal, or subcutaneous infiltrate of small- to medium-sized CD4⁺ T cells with histiocytes and admixed granulomas.⁴ Epidermotropism and Pautrier microabscesses often are limited or absent but can be seen. The neoplastic T cells involved in ATLL commonly express CD3, CD4, CD25, CD30, and programmed death 1, and T-cell clonality frequently is present.^11,22 Even with staining, diagnosis of ATLL is difficult, as it requires positive testing for HTLV-1 antibody as well as monoclonal integration of HTLV-1 proviral DNA into tumor cells.¹¹ Clinical information is vital in coming to this diagnosis, as there is such great histopathologic overlap with other cutaneous T-cell lymphomas.²³

Differential Diagnosis
The differential diagnosis includes other small- or medium-sized T-cell lymphomas. The chronic and smoldering types can be difficult to distinguish from mycosis fungoides. Primary cutaneous CD4⁺ small- or medium-sized pleomorphic T-cell lymphoma also must be considered, though it often is confined to the skin and can be differentiated from ATLL, as systemic involvement is commonly present in the latter.

Treatment
Treatment decisions should be made based on the subclassification and prognostic factors at the time of diagnosis. High doses of interferon alfa and zidovudine may show some benefit, but many cases require multiagent chemotherapy.²² The only possible curative treatment is allogeneic stem cell transplant. Mogamulizumab, an antichemokine receptor 4 monoclonal antibody, has demonstrated some ATLL antitumor activity.²⁴