Premium
Nontuberculous mycobacteria‐associated spindle cell pseudotumor of the nasal cavity: A case report
Author(s) -
Ohara Kentaro,
Kimura Tokuhiro,
Sakamoto Koji,
Okada Yasunori
Publication year - 2013
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1111/pin.12059
Subject(s) - pathology , histiocyte , biology , epithelioid cell , immunohistochemistry , nasal cavity , phenotype , lesion , medicine , anatomy , gene , biochemistry
Mycobacterial spindle cell pseudotumor ( MSP ) is a rare mass‐forming lesion caused by mycobacterial infection, mostly in immunocompromised patients. Since it is composed of a proliferation of spindle‐shaped fibrohistiocytic cells without forming epithelioid cell granulomas, histological distinction from other spindle cell lesions is often difficult and its pathophysiology is poorly understood. MSP arising in the nasal cavity is extremely rare, and only two cases have been reported previously. Here we report a case of MSP of the nasal cavity in an 83‐year‐old man with no evidence of immunodeficient state. The resected tumor consisted of spindle cells, which contained numerous acid‐fast bacilli in the cytoplasm. By polymerase chain reaction and sequencing using DNA extracted from the paraffin sections, the bacilli were identified as M ycobacterium intracellulare . Immunohistochemistry revealed that the spindle cells were positive for CD 68, CD 11c and S 100 protein, confirming the histiocytic nature of these cells. They were also positive for CD 163 and CD 204, suggesting that they showed a phenotype similar to alternatively activated ( M 2) macrophages and the phenotype might contribute to the maintenance of mycobacterial infection despite apparent immunocompetence of the host.