ALK-Negative Anaplastic Large Cell Lymphoma With Rare Scalp Involvement: A Case Report and Literature Review

Anaplastic large-cell lymphoma (ALCL) is a rare type of T-cell lymphoma characterized by a clonal proliferation of atypical large cells. Here, we describe a 63-year-old man presenting with subcutaneous nodules on the scalp and anterior chest wall, right axillary lymphadenopathy, and systemic B symptoms. Positron emission tomography imaging revealed hypermetabolic activity in the scalp, chest wall, and axillary lymph nodes, suggestive of aggressive lymphoma. Histopathological analysis confirmed lymphoma with atypical large cells, and immunohistochemistry showed that both ALK and CD30 were negative, making the diagnosis atypical. This case illustrates the rarity of scalp involvement in ALK-negative ALCL and underscores the importance of a multidisciplinary approach, integrating clinical, imaging, and histological findings for accurate diagnosis and management.