PRIMARY CUTANEOUS γδ T-CELL LYMPHOMA:REPORT OF A RARE ENTITY George SA[1], Al Shayeb ARAA [2], Francis I[3]. Copyright Colin Purrington (http://colinpurrington.com/tips/academic/posterdesign). [1] Pathology Department, Mubarak Al-Kabeer Hospital ,Kuwait [2] Medicine Department, Mubarak Al-Kabeer Hospital ,Kuwait [3] ] Pathology Department, Mubarak Al-Kabeer Hospital ,Kuwait [ b a Conclusions Background Primary cutaneous γδ T –cell lymphoma(PCGD-TCL) are rare, representing approximately 1% of all cutaneous T-cell lymphoma, composed of a clonal proliferation of mature activated γδ T –cells with a cytotoxic phenotype which was previously known as subcutaneous panniculitis-like T-cell lymphoma with a γδ phenotype. PCGD-TCL occur in adults, often presenting with generalized skin nodules, indurated plaques, ulcerations and preferentially affect the extremities Neoplastic γδ T –cells show epidermotropic, dermal and subcutaneous involvement, the latter can mimic panniculitis. PCGD-TCL often shows CD4-,CD8-,CD56+/-, βF1- and TCRδ-1 positive phenotype. The diagnosis is confirmed by the identification of a clonal rearrangement of the δ TCR gene by PCR. The main differential diagnoses are α/β subcutaneous panniculitis like T-cell lymphoma and lupus panniculitis. It can be associated with complications such as hemophagocytic syndrome and multi-organ failure. PCGD-TCL are aggressive lymphomas resistant to multi-agent chemotherapy and/or radiation and have a poor prognosis with a median survival of approximately 15 months.. PCGD-TCL, an extremely rare and highly malignant lymphoma usually run an aggressive course and portend a poor prognosis. Patients with subcutaneous fat involvement have a more unfavourable prognosis. Prompt diagnosis and intense poly-chemotherapy is essential. Allogenic stem cell transplantation appears to be a promising therapeutic option for these lethal lymphomas. c Figure 1a &b Indurated and ulcerated plaques and nodules in the skin Figure 1c Penile ulcer Figure 1d PET SCAN with hyper-metabolic lesions in the subcutis. Figure 2a Epidermal ulceration Figure 2b Tumor cells infiltrating the adnexa Figure 2c Perineural involvement CD3 immunopositive tumor cells Case Summary A 24-year-old male presented with two weeks history of ulcerated and indurated plaques and nodules on the skin predominantly involving the lower limbs and genital ulcer, associated with fever and hepatosplenomegaly. PET-CT scan demonstrated multiple cutaneous and subcutaneous soft tissue lesions scattered throughout the body and hyper-metabolic genital ulcer ,suspicious of cutaneous T-cell lymphoma. A skin biopsy was performed and subsequent histopathology showed ulcerated epidermis, deep dermal and subcutaneous infiltrate of large blasts with irregular nuclei containing coarsely clumped chromatin, inconspicuous nucleoli and increased mitotic activity. Perineural and angioinvasion and foci of necrosis were demonstarted. These tumor cells were immunopositive for CD2, CD3, CD56, GRANZYME B and negative for CD4, CD5, CD8, & CD7 . Based on histology and immunohistochemistry, a diagnosis of PCGD-TCL was made. The patient is curremtly undergoing chemotherapy. Figure 3 Negative CD8 & CD4 immunostains in the tumor cells High Ki-67 proliferation index in the tumor cells CD56 immunostain positive in the tumor cells References WHO classification of tumours of h aemotopoietic and lymphoid tissues.4th edition.