SPTCL : Intro & Clinical
Introduction: Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma that preferentially involves subcutaneous fat. It can mimic lobular panniculitis. Before it was officially recognized as a distinct entity by the WHO in 2001, SPTCL cases were variously labeled as malignant histiocytosis, histiocytic lymphoma, cytophagic histiocytic panniculitis, histiocytic medullary reticulosis, and Weber-Christian panniculitis. Alpha-beta vs Gamma-delta T-cell Lymphoma: A distinction is made between cases with alpha-beta vs gamma-delta T-cell lineage. By definition, SPTCL should have alpha-beta T-cell phenotype as confirmed by positivity for Beta F1. They are CD4-, CD8+, and CD56- and have favorable prognosis. Cases that express gamma-delta receptor are classified separately as gamma-delta cutaneous T-cell lymphoma. They are aggressive tumors and have CD4-, CD8-, and CD56+ phenotype. Clinical Features: SPTCL is seen over a wide age range (median age 36 years) with a female predilection. About 20% of patients are under 20 years old. Patients develop solitary or multiple, firm, erythematous/violaceous, deep-seated plaques or nodules without ulceration. The size ranges from <1 cm to >20 cm. The usual location is the extremities and trunk, followed by face, neck, axilla, inguinal region, and buttocks. Most patients have generalized lesions at presentation. About half the patients have B symptoms consisting of fever, malaise, fatigue, and weight loss. Anemia, cytopenias, raised ESR, and abnormal liver function tests are common. Usually there is no lymphadenopathy. About 20% of cases (especially pediatric patients) may present with hemophagocytic syndrome (hepatosplenomegaly, coagulopathy with bleeding, fever, weight loss, and myalgias). Association with Autoimmune Disorders: SPTCL has been observed in patients with immune dysregulation. Many patients have history of systemic lupus erythematosus (20% of cases) or have received immune modulatory drugs or immunosuppressive therapy (after organ transplantation). Lupus erythematosus panniculitis (LEP) and SPTCL share clinical and morphologic similarities and they may represent the two ends of the spectrum of the same disease process. Image source: Bagheri F et al. An Illustrative Case of Subcutaneous Panniculitis-like T-cell Lymphoma: A Case Report. Journal of Skin Cancer, Volume 2011, Article ID 824528; used under Creative Commons Attribution License.