Sarcomatoid variant of ALK- anaplastic large cell lymphoma involving multiple lymph nodes and both lungs with production of proinflammatory cytokines: report of a case and review of literature.

Sarcomatoid variant of anaplastic large cell lymphoma (ALCL) is one of the rarest histologic variants of ALCL that consists of large, bizarre, often spindle-shaped, neoplastic cells resembling a soft tissue sarcoma. We report here such a case of ALCL with both pulmonary and multiple nodal involvement in a 47-year-old woman who initially presented with fever, cough, sputum, itching skin, and weight loss. The initial transbronchial lung biopsy showed discohesive pleomorphic malignant cells in a strong inflammatory milieu reminiscent of inflammatory malignant fibrous histiocytoma (MFH). Subsequent cervical lymph node biopsy revealed a spindle cell sarcoma predominantly composed of plump spindle and oval neoplastic cells in interweaving fascicles, with sparse inflammatory infiltrates, resembling pleomorphic-storiform type of MFH. However, these tumor cells in the lung and node lesions revealed essentially similar immunohistochemical features that were positive for CD30, EMA, TIA-1, granzyme B, and fascin, but negative for anaplastic lymphoma kinase (ALK), and T- or B-lineage-specific marker. The spindled cells stains diffuse strong positive for smooth muscle actin (SMA), along with vimentin. Further studies showed that the tumor produced large quantities of the proinflammatory cytokines interleukin-2 (IL-2), IL-6, and IL-8, which we believe may contribute to the pathogenesis of sarcomatoid transformation of this tumor, and was associated with the patient's inflammatory symptoms. To the best of our knowledge, this is the first reported case of sarcomatoid variant of ALK-negative ALCL with null cell phenotype and in situ production of proinflammatory cytokines presenting as multiple nodes and pulmonary involvement.