Subcutaneous Panniculitis-Like T Cell Lymphoma: Approach to Differential Diagnosis on Cytology

Sighting a case of subcutaneous panniculitis-like T cell lymphoma (SPTCL) in cytology is very rare in a clinical scenario. Among the differential diagnoses (D/D) of a subcutaneous nodule undergoing fine needle aspiration cytology (FNAC), it is hardly considered in the list. The common D/D on cytology would be panniculitis or a non-SPTCL lymphoma. To make a correct cytological diagnosis, the pathologist has to meticulously observe the type of inflammatory infiltrate, their morphology, the intimate admixture of the fat lobules, and background necrosis or macrophages. This article describes the cytological picture, D/D, and the prognostic factors associated with SPTCL in a young male. He was suspected of SPTCL after FNAC and later confirmed on histopathology with specific immunomarkers. We do not recommend the confirmation of SPTCL on cytology however, we would like to stress that it can be picked up and differentiated from its mimickers on FNAC.