Histopathological features of SPTCLs and detection of HAVCR2^Y82C mutations. (A) Excisional biopsy specimen of a 16-year-old female patient with an SPTCL (SP04) exhibited adipocytic rimming by CD8-positive lymphocytes along with prominent necrosis. This patient was confirmed by using WES to have a germline homozygous HAVCR2^Y82C mutation. (B) Lipogranulomatous inflammation was observed in a 54-year-old female patient (SP44), and TGS revealed heterozygous HAVCR2^Y82C mutations. SP14 harbored heterozygous HAVCR2^Y82C mutations, which could be inferred from double peaks on the electropherogram. (C) A 45-year-old female patient (SP52) with the HAVCR2^WT genotype had both necrosis and granuloma formation. (D) Lipogranulomatous inflammation was observed in the HAVCR2^WT SPTCL of a 53-year-old woman (SP39).