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Case of the Week #218

28 September 2011 Ė Case of the Week #218

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Case of the Week #218

Clinical History:

A 35 year HIV+ man had diffuse lymphadenopathy (retroperitoneal, paraaortic, supraclavicular, inguinal and mesenteric) and increased FDG uptake on PET CT. His left supraclavicular node was 3.1 cm. A CT guided biopsy of a retroperitoneal lymph node was performed.

Micro images:

       

What is your diagnosis?































Diagnosis:

Mycobacterial spindle cell pseudotumor of lymph nodes

Discussion:

Mycobacterial spindle cell pseudotumor of lymph nodes is a disorder associated with HIV+ patients, often with involvement of many sites. It may also affect infants after bCG vaccination (Zhonghua Bing Li Xue Za Zhi 2001;30:89) or occur post-transplant (Am J Clin Pathol 1985;83:524).

Morphologically, the lymph nodes show a partial or complete effacement with a storiform pattern of bland spindle cells, some with vacuoles. There are also numerous vessels lined by plump endothelial cells, plasma cells and lymphocytes. There are no multinucleated tumor cells and no foamy histiocytes. The spindle cells are actually macrophages with large numbers of mycobacteria (Am J Surg Pathol 1992;16:276). Intraoperative touch imprints demonstrate numerous intracellular organisms (Arch Pathol Lab Med 1995;119:811).

The tumor cells are immunoreactive for CD68, S100 and AFB and negative for CD34:

       

Left to right: S100, AFB, CD34

The differential diagnosis includes:
Kaposi's sarcoma: has slit-like spaces and mitotic figures; cytoplasm is not granular or acidophilic; spindle cells are CD31+ and CD34+, but negative for S100, CD68 and AFB (Am J Surg Pathol 1999;23:656)
Smooth muscle tumor: positive for actin and desmin, negative for S100, CD68 and AFB

Treatment consists of antiretroviral therapy for HIV and antibiotics.

Nat Pernick, M.D., President
PathologyOutlines.com, Inc.
30100 Telegraph Road, Suite 408
Bingham Farms, Michigan (USA) 48025
Telephone: 248/646-0325
Email: NatPernick@Hotmail.com
Alternate email: NatPernick@gmail.com