Primary cutaneous CD4+/CD56+ hematodermic neoplasm (blastic NK‐cell lymphoma): a case report

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A previously healthy 44‐year‐old Chinese man presented with a nonitching, painless, skin lesion on the right lateral abdomen of 1‐year duration. This lesion presented initially as a nodule of approximately 0.5 cm in diameter, which eventually grew to the size of an egg by August 2006. The patient had experienced no systemic symptoms, and his past medical and family history were noncontributory. Physical examination was normal except for the skin lesion. Peripheral lymph nodes were not palpable. Skin examination showed a lobulated, contusiform, brownish, infiltrated nodule with a wide base on the right lateral abdomen (Fig. 1).A lobulated, contusiform, brownish, infiltrated nodule with a wide base on the right lateral abdomenimage Histologic examination of a biopsy specimen taken from the lesion revealed the presence of a dense dermal lymphomatous infiltrate with a diffuse growth pattern, which extended into the subcutis. The Grenz zone was present. No signs of necrosis, karyorrhexis, hemophagocytosis, or angiocentric infiltrate were found (Fig. 2a). The tumor was composed of medium‐sized pleomorphic cells with dispersed chromatin and absent or indistinct nucleoli, resembling lymphoblasts. Frequent mitosis was seen (Fig. 2b).(a) Dense dermal lymphomatous infiltrate with a diffuse growth pattern. The Grenz zone was present. No signs of necrosis, karyorrhexis, hemophagocytosis, or angiocentric infiltrate were found (hematoxylin and eosin, ×40). (b) The tumor was composed of medium‐sized pleomorphic cells with dispersed chromatin and absent or indistinct nucleoli, resembling lymphoblasts. Frequent mitosis was seen (hematoxylin and eosin, ×400)image Immunohistochemical studies revealed the reactivity of more than 90% of the cells with CD56, CD4, and CD43 (Fig. 3a,b). Immunostaining for CD3, CD8, CD20, CD30, CD68, CD79a, CD99, T‐cell intracellular antigen‐1 (TIA‐1), Gallyas–Braak silver (GB), L26, Kp‐1, myeloperoxidase (MPO), and terminal deoxynucleotidyl transferase (TdT) was either weak or negative. Clonal rearrangement of the T‐cell receptor (TCR) was not detected by polymerase chain reaction (PCR). Epstein–Barr virus (EBV) staining of the skin biopsy specimen was negative.Immunohistochemical studies revealed the reactivity of more than 90% of the cells with CD4 (a) and CD56 (b) (SP, streptavidin‐perosidase, ×400)image Laboratory examinations, including complete blood examination with peripheral blood smear, liver enzymes, electrolyte levels, kidney function, antinuclear antibody, and urine analysis, were all normal. EBV antibodies were negative. Chest radiograph, nasal bone X‐ray, and bone marrow biopsy revealed no abnormal findings. Computed tomography of the nasal cavity, abdomen, and pelvis was normal. On the basis of the aforementioned clinical, histopathologic, and immunohistochemical findings, the patient was diagnosed with primary cutaneous CD4+/CD56+ hematodermic neoplasm [blastic natural killer (NK)‐cell lymphoma]. After receiving a diagnosis of a very aggressive malignancy, the patient refused chemotherapy until right groin lymphadenopathy occurred 6 months later. In February 2007, the lesion was excised and showed the same pathologic features, consistent with cutaneous blastic NK‐cell lymphoma. From March 2007, the patient received five courses of polychemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone (CHOP). The lymphadenopathy disappeared after one cycle of chemotherapy. The patient received four more cycles of chemotherapy and no recurrence was observed over the following 6 months.