Primary cutaneous ALK-negative anaplastic large cell lymphoma: A case report

INTRODUCTION AND IMPORTANCE: Anaplastic lymphoma kinase negative anaplastic large cell lymphoma (ALK-ALCL) is a rare CD30-positive peripheral T-cell lymphoma with a low incidence of ALK-ALCL, which mainly involves lymph nodes and, in a minority of patients, extra-nodal tissues. The etiology is unknown, and the incidence is higher in males. CASE PRESENTATION: We report a case of primary cutaneous ALK-ALCL. On light microscopy, the cells showed marked heterogeneity with abundant cytoplasm and numerous nuclear schizonts, and immunohistochemistry showed large mesenchymal cells strongly positive for CD30 and negative for ALK gene products. Magnetic resonance imaging showed nodular shadows with low T1 signal and high T2 signal. Follow-up was six months and no recurrence was seen. CLINICAL DISCUSSION: PC-ALCL is prevalent on the trunk, face and extremities. Its clinical manifestations are inert, presenting as isolated or limited reddish-brown papules, nodules, or swellings of human skin, single or multiple, with advanced ulcerative lesions with central necrosis and dyke-like elevated margins, and some lymph node involvement. Histopathology showed diffuse infiltration of tumor cells with abundant cytoplasm, pronounced nuclear fission, and marked vascular centrality of the tumor infiltrate. PC-ALCL should be distinguished from systemic ALCL. CONCLUSION: PC-ALCL has a low incidence rate and is characterized by recurrent recurrence, and the site of the lesion and the extent of injury are the main factors affecting the prognosis. Relevant imaging examinations help to identify the extent of involvement and depth of invasion of this disease, and play an important role in the diagnosis and treatment of this disease.