In the long differential diagnosis of scalp nodules in children, subcutaneous granuloma annulare (SGA) generally is not included. In our dermatology clinic, we encountered a young child who presented with multiple evolving subcutaneous nodules of the scalp that, after evaluating the results of a biopsy, were determined to be SGA.
Case Report
A 15-month-old white girl presented with subcutaneous scalp lesions. The patient's mother noted the nodules had appeared 5 to 6 months prior over a period of several days following an episode of pneumonia. Her mother also noted that the lesions had appeared "swollen" and had decreased in size over several weeks prior to presentation. Drainage was never noted, but the nodules were tender. The patient's medical history was notable for pneumonia that occurred 5 to 6 months prior to presentation, sleep apnea, ear infections, and reflux. The patient had no significant family or social history. The review of systems was negative for any constitutional symptoms including fever, chills, weight loss, night sweats, and visual or neurologic abnormalities. The patient originally presented to her pediatrician, whose initial clinical differential diagnosis included dermoid cysts, histiocytosis, neuroblastoma, and epithelioid sarcoma. The workup included a complete blood count, differential white blood cell count, sedimentation rate, comprehensive metabolic panel, and serum ferritin levels, results of which were all within reference range. Results of a skull radiograph demonstrated ill-defined lucencies overlying the posterior parietal and inferior occipital bones on the lateral view. This was followed by a computed tomography of the head taken with and without contrast, the results of which demonstrated normal sutures with no evidence of intracranial masses or bony lesions. The patient was referred to the departments of pediatric neurosurgery and hematology-oncology, which recommended and performed an excisional biopsy with the patient under general endotracheal anesthesia. Pathology results, discussed later in detail, showed features consistent with granuloma annulare. The biopsy specimen also was examined for the presence of abnormal lymphocytes, and no evidence of B-cell light chain restriction, abnormal T-cell immunophenotype, or clonal T-cell expansion was found. At this point, the patient was referred to dermatology and seen in our clinic for consultation. Histologic sections stained with hematoxylin-eosin (H&E) demonstrated loosely arranged areas of granulomatous inflammation primarily consisting of lymphocytes and histiocytes. Focally, the lymphocytes and histiocytes formed loose palisades next to areas of necrosis in the dermal collagen (Figure 1). The granulomatous inflammation was present adjacent to skeletal muscle. There were occasional areas of clearing dispersed throughout both the inflammation and the adjacent dermal collagen. These areas of clearing contained a wispy, faint basophilic material (Figure 2). Suspected mucin deposition in these cleared areas was confirmed by positive staining results with colloidal iron (Figure 3). Results of a diastase periodic acid-Schiff stain for fungus was negative, as was an auramine-rhodamine stain for acid-fast bacilli. No epidermis was present on the biopsy specimen.
Results of a physical examination revealed the patient was an active, healthy-appearing, white female child within the normal limits for weight and height. Results of a total-body skin examination was unremarkable except for multiple firm, adherent subcutaneous nodules that were tender and distributed on the patient's anterior hairline and throughout her scalp. Erythema was not noted. No other nodules were seen on the rest of the patient's body, and no lymphadenopathy was detected. Clinically, the results of her examination were consistent with SGA, and the histopathology results confirmed the diagnosis. Treatment options for this patient included topical corticosteroids, intralesional corticosteroids, and excision (which would have required general anesthesia). Extensive counseling was provided to the patient's mother regarding the benignity of the lesions. Because there were numerous lesions, a decision was made to pursue conservative management. Hydrocortisone valerate 0.2% cream applied twice daily was prescribed. At follow-up 7 months later, the lesions had resolved.
Case Review Because SGA is uncommon and often is mistaken for more alarming entities, we believed it would be beneficial to examine other cases of SGA encountered at our facility. With approval from our internal review board, we reviewed clinical data from July 1995 through June 2004 of all patients who had histopathologic reports labeled as SGA; deep granuloma annulare; or palisading granuloma without evidence of rheumatoid disease, gout, or infection. The location of the lesions on which biopsies were performed, the number of lesions, evidence of recurrence, as well as the age, sex, and race of the patients were noted. Histopathologic slides were reviewed and the stains that were obtained were noted. These data are found in Table 1.