Subcutaneous panniculitis‐like T‐cell lymphoma in the pediatric age group: A lymphoma of low malignant potential

BACKGROUND: Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare neoplasm of mature αβ cytotoxic T-cells. Most commonly occurring in young adults, few reports are described in children. A separate analysis of a significant cohort of pediatric patients has not previously been performed. PROCEDURE: We analyzed the pathology including molecular results as well as available clinical data from 16 pediatric patients (age 5 months to 21 years) who had a total of 19 biopsies submitted to the National Cancer Institute from 1999 to 2011. This included 6 males and 10 females. RESULTS: Most patients (10/16, 62.5%) had multiple skin lesions at the time of biopsy. Histologic features included rimming of adipocytes by atypical lymphocytes, fat necrosis, and karyorrhectic debris. Four biopsies showed only partial involvement by lymphoma; and plasma cells were identified in 14/19 (74%) cases, including three in which they were focally prominent. The neoplastic cells in general were positive for CD3, CD8, TIA-1, and βF1 and were negative for CD4 and CD56. CD5 expression was weak to negative in 5/8 cases (63%). A clonal T-cell receptor gene rearrangement was demonstrated in 11/17 (65%). Patients were treated with a variety of agents. While 5/9 (56%) patients had evidence of recurrent skin lesions, no deaths were attributed to disease for the seven patients with follow-up information. CONCLUSIONS: Pediatric SPTCL shares many clinical and pathologic features with adult SPTCL. The presence of partial involvement or admixed plasma cells makes the differential diagnosis with reactive conditions challenging in some cases.