Mycobacterial spindle cell pseudotumor of the appendix vermiformis in a patient with AIDS

Abstract

Mycobacterial pseudotumor (MP) is a rare pathologic presentation of both Mycobacterium tuberculosis and non-tuberculous mycobacterial disease, hitherto reported to occur only in immunosuppressed patients with or without human immunodeficiency virus infection. This lesion shares close pathologic resemblance to certain mesenchymal neoplasms, particularly Kaposi's sarcoma (KS), from which it must be properly differentiated due to distinct prognosis and therapy. We report a case of MP obliterating the lumen of the appendix vermiformis in a 34-year-old patient who died of complications of AIDS at our hospital in Rio de Janeiro. A total of 24 cases of MP (including our patient) have been described in the literature. MP has been found especially in lymph nodes, but extranodal lesions have been described in the skin, spleen, lung, bone marrow, brain and, in our patient, the appendix vermiformis. We offer a review of the other 23 published case reports of MP in both HIV-infected and uninfected patients and discuss the pathologic features that differentiate MP from KS.

Myocbacterium-Avium Intracellulare Associated Inflammatory Pseudotumor of the Anterior Nasal Cavity

“…Complete surgical resection, if possible, is the treatment of choice with the exception of orbital lesions [5]. Recurrence can occur and has been reported in approximately 25% of the cases and is usually treated by repeated surgical excisions [15]. In few cases spontaneous regression may also occur [15].…”

“…Recurrence can occur and has been reported in approximately 25% of the cases and is usually treated by repeated surgical excisions [15]. In few cases spontaneous regression may also occur [15].…”

Mycobacterium microti infection associated with spindle cell pseudotumour and hypercalcaemia: a possible link with an infected alpaca

“…MSCP is a rare condition usually associated with immunosuppression and characterised by a benign proliferation of spindle cells 3. Most previous cases have occurred in HIV-infected individuals4 but in this case, the likely cause of immunocompromise was previous use of immunosuppressant drugs.…”

“…To date, approximately 22 human cases of MSCP have been described. Lymph nodes are frequently involved,5 although extranodal involvement has been described in a variety of tissues including brain and appendix 3 , 4. Most previous cases have been attributed to environmental mycobacteria, mainly Mycobacterium avium intracellulare 4.…”

Human Immunodeficiency Virus–Related Gastrointestinal Pathology: A Southern Africa Perspective With Review of the Literature (Part 1: Infections)

“…Mycobacterial spindle cell pseudotumors may also occur. 35 Distinction of GI TB from Crohn disease may be difficult, particularly in immunocompetent patients with HIV, although Crohn disease is rare in indigenous African patients 36 and is uncommon in the setting of HIV. 37 The presence of abundant, large (.400 mm), confluent granulomas demonstrating fibrillogranular (caseous) necrosis, disproportionate submucosal inflammation, histiocyte palisading at the base of ulcers, and the absence of mucosal chronicity away from foci of active disease all suggest tuberculosis.…”