DISCUSSION
Chromophobe RCC is a rare form of RCC that has a recurrence-free survival of > 80% when treated in early stages.2 These neoplasms represent only 3000 to 6000 new cases of RCC annually, with an even lower incidence (6% to 7%) resulting in metastatic disease. The liver is the most common site of metastases (39%).2 Previously reported metastatic chRCC hepatic lesions have been incidentally noted on imaging with asymptomatic clinical presentations. In contrast to our patient, most documented cases report metastatic chRCC as a solitary hepatic lesion.3-7
A noteworthy genetic association with ChRCC is the Birt-Hogg-Dubé syndrome, which is an autosomal-dominant genetic disorder that results from germline mutations in the tumor suppressor folliculin gene located on chromosome 17.8 This syndrome is characterized by the development of various benign and malignant tumors, particularly chRCC. Our patient appeared to have a sporadic chRCC with the absence of other tumors and negative family history for malignancies. On his initial staging imaging, in accordance with National Comprehensive Cancer Network guidelines, our patient was identified only as having a 10-cm right renal mass and 1 benign regional lymph node with an otherwise unremarkable computed tomography of the chest, abdomen and pelvis, corresponding to stage 2 cancer.
Common causes of hepatic abscesses, the other potential diagnosis of concern for the patient, were biliary infections, portal vein ascension from abdominal sources, arterial translocation due to bacteremia, and local invasion due to suppuration of adjacent tissue.9 Incidence for hepatic abscesses increases with comorbidities such as diabetes, cirrhosis, malignancy, immunosuppression, and malnutrition.10 Candida is also a common culprit when there are multiple, small abscesses, often in immunocompromised patients.11 Given the high mortality rates associated with hepatic abscesses, prompt treatment is imperative.10,12 Since the clinical signs and symptoms for hepatic abscesses are nonspecific (abdominal pain, fever, and malaise) and liver function tests can vary, the diagnosis primarily relies on imaging or tissue sampling.9
It can be difficult to distinguish abscesses from metastatic lesions based on imaging alone without microbiologic and pathologic confirmation.11,13,14 There are certain radiologic characteristics that have been found to favor abscesses over metastasis, including parenchymal enhancement, arterial rim enhancement, and perilesional hyperemia.15 However, previously described hallmark characteristics of hepatic abscesses, such as the “cluster sign” demonstrating early stages of abscess coalescence, have also been seen in some hepatic metastases.16
CONCLUSIONS
This patient highlights the presentation of a rare case of metastatic chRCC with multiple hepatic lesions. While often differentiated clinically, radiographically, or histologically, malignancy and abscess can be difficult to differentiate in a patient with fevers and leukocytosis with hepatic lesions.17 Early diagnosis of hepatic abscesses and initiation of antibiotic therapy are essential. In cases when it is challenging to characterize the hepatic lesions, repeated tissue sampling and imaging can help direct therapy. Attention should be paid to a previous history of malignancy and should raise suspicion for metastatic disease, particularly with misleading imaging studies and tissue samples.
Acknowledgments
This case was presented as a poster presentation at the Tri-Service American College of Physicians Meeting, September 7-10, 2022, San Antonio, Texas.