Clinicopathologic Determinants of Subcutaneous Panniculitis-like T-Cell Lymphoma (SPTCL) Clinical Outcomes: Analysis of a Pooled Database

Introduction Subcutaneous Panniculitis-like T-cell Lymphoma (SPTCL) is a rare subtype of extra-nodal Peripheral T-cell Lymphoma. SPTCL was initially described as an aggressive T-cell lymphoma frequently associated with hemophagocytic syndrome (HPS) and requiring aggressive multiagent chemotherapy. In 2005, this entity was restricted to SPTCL with αβ phenotype, a less aggressive entity compared to its γδ counterpart, currently known as primary cutaneous γδ T-cell lymphoma. We conducted this analysis to explore the determinants of clinical outcomes in this little-known subtype of Peripheral T-cell Lymphoma.

Methods To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 214 cases. Descriptive statistics were calculated. Cox proportional-hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS) and disease-free survival (DFS).

Results A total of 214 patients with confirmed SPTCL diagnosis were identified. The median age was 34 years with a peak incidence between ages 13 and 26. There was a female predominance with F:M ratio of 1.7. Upon presentation, 12% had lymphadenopathy, 12% had hepatosplenomegaly, and 27% had bone marrow involvement. No extra-nodal or extra-cutaneous involvement were reported. The most common clinical presentations were nodular skin changes (87%) followed by constitutional symptoms (57%). Fifteen and ten percent of SPTCL patients had history of immune-deregulatory disorders and immunosuppressive therapies, respectively. HPS occurred in 24% of the cases. Fat necrosis and dermal involvement were noted in 9% and 17%. The median duration of symptoms prior to diagnosis was 4 months. Median DFS of the whole group was 60 months. While the median OS of the whole group was not reached, the mean overall survival was 73 months. OS was not impacted by sex, constitutional symptoms, immunocompromising factors, presence of lymphadenopathy, hepatosplenomegaly, or bone marrow involvement. OS was not impacted by histological or immunohistochemical features though there was a trend for better OS as well as DFS for TIA-1 expressors. OS and DFS declined as age increased from <19 to 20-39 and >40 years. HPS negatively impacted OS and DFS, but with borderline significance with the latter. Attaining complete remission positively impacted both OS and DFS. Stem cell transplant positively impacted OS and DFS, but with borderline significance with the former.

Conclusions This study presents a comprehensive clinicopathologic data from a pooled cohort of patients with SPTCL. It describes the clinicopathologic features of SPTCL and identifies major clinical, immunohistochemical, and therapeutic modalities that are major determinants of OS and DFS in this rare disease.

No relevant conflicts of interest to declare.