Mycobacterial spindle cell pseudotumor (MSP) of the nasal septum clinically mimicking Kaposi's sarcoma: case report.

Mycobacterial spindle cell pseudotumor (MSP) is a rare benign lesion characterised by local proliferation of spindle - shaped histiocytes containing acid - fast atypical mycobacteria, clinically resembling Kaposi's sarcoma. Most cases of MSP reported so far affected immunodeficient patients or patients receiving immunosuppressive medication. We report a case of MSP affecting the nasal septum of a 76-year-old man, a location that has not been published so far concerning the manifestation of MSP. In conclusion, our case report points toward MSP as a very rare pseudomalignant lesion that should be included into deliberations concerning the differential diagnosis of circumscribed expansile nodular proliferations of the nasal septum clinically mimicking Kaposis's sarcoma or other mesenchymal neoplasms.