Subcutaneous Panniculitis-like T-Cell Clonal Proliferation in an Infant. Lymphoma or Reactive Lymphoproliferation?

Abstract

Subcutaneous panniculitis-like T-cell clonal proliferation is commonly seen as a cytotoxic subcutaneous lymphoma arising mainly in adults. This type of lymphoid proliferation in children, particularly in infants, is extremely rare. In most such cases, the prognosis is excellent even if it is associated with a hemophagocytic syndrome (HPS). Some cases may even regress spontaneously. The case presented here concerns a 6-month-old infant who presented with panniculitis lesions associated with an HPS that started 1 week after a chickenpox infection. The histologic findings showed a marked lobular panniculitis with extensive hyaline necrosis of adipocytes and massive infiltration of clonal small-to-medium lymphocytes with a cytotoxic, CD56 − , β-F1 + phenotype. In addition, the same lymphocytic proliferation was also observed in the upper dermis and the epidermis. Complete and stable remission of both cutaneous lesions and systemic manifestations was obtained with nonaggressive therapy consisting of systemic steroids followed by cyclosporin A. This observation demonstrates that in a young child, a clonal T-cell lymphoproliferation in the skin, even when it has an aggressive histologic appearance and is combined with an HPS, need to not be managed aggressively with chemotherapy. Because the disorder began a few days after a viral infection, it should be seen as a reactive clonal T-cell lymphoproliferation rather than a true T-cell lymphoma.