Diagnosing Spindle Cell Variant of Primary Cutaneous B-Cell Lymphoma: Potential Pitfalls and Solutions.

Spindle cell variant of cutaneous B-cell lymphoma is a rare entity which poses a diagnostic difficulty. The differential diagnosis of cutaneous spindle cell lesions is broad, and often includes sarcoma, carcinoma, and melanoma. Lymphoma with spindle cell morphology is frequently only considered after exclusion of more common etiologies. Among these rare cases of lymphoma with spindle cell morphology, a majority prove to be of B-cell origin. Following the diagnosis of cutaneous lymphoma, a thorough clinical evaluation must be conducted to determine if the lesion represents primary cutaneous lymphoma or secondary cutaneous involvement by a systemic process, as these have distinct classifications, prognoses, and treatments.