World J Mens Health.  2014 Dec;32(3):184-188. 10.5534/wjmh.2014.32.3.184.

Diagnosis of a Gastrointestinal Stromal Tumor Presenting as a Prostatic Mass: A Case Report

• Huh JS
• Park KK
• Kim YJ
• Kim SD

• KMID: 2320783
• DOI: http://doi.org/10.5534/wjmh.2014.32.3.184

Abstract

Gastrointestinal stromal tumors (GISTs) are an unusual and heterogeneous group of spindle cell tumors that can also appear on the exterior of the gastrointestinal tract (extra-GISTs). Despite the fact that extra-GISTs or large rectal GISTs can lead to the clinical impression of a prostatic mass, these tumors are, in general, excluded in the differential diagnosis of spindle cell tumors observed on prostate needle biopsy. Here, we present, in detail, a case of an extra-GIST identified on prostatic biopsy; the tumor was previously believed to be a primary prostatic stromal sarcoma in the differential diagnosis. Every investigator should check for KIT (CD117) in immunohistochemical staining to rule out an extra-GIST prior to diagnosing a solitary prostatic tumor, specialized prostatic stromal tumor, or leiomyosarcoma on prostate needle biopsy.

Keyword

Gastrointestinal stromal tumors; Prostate

MeSH Terms

Biopsy
Biopsy, Needle
Diagnosis*
Diagnosis, Differential
Gastrointestinal Stromal Tumors*
Gastrointestinal Tract
Humans
Leiomyosarcoma
Prostate
Research Personnel
Sarcoma

Figure

• 

  Fig. 1 (A, B) Transrectal ultrasonography revealed that the huge prostatic mass measuring 97×88×84 mm was well capsulated with internal hemorrhage. The mass was isolated from the surrounding structures. (C, D) Magnetic resonance image of the prostate showed an enlarged prostatic mass with hemorrhagic necrosis. The prostatic mass had a large size (110×85×86 mm) with heterogeneous enhancement and displaced bladder (arrow) anteriorly and rectum (arrowhead) posteriorly. This implies that the tumor was mainly localized within the prostate and there was no definite evidence of the direct invasion of adjacent organs.

• 

  Fig. 2 (A) The tumor is composed of relatively uniform spindle cells with vesicular nuclei and eosinophilic cytoplasm. These cells are arranged in whorled or fascicular pattern. There is no significant nuclear pleomorphism (H&E, ×200). (B) CD117 (c-kit) staining shows diffuse strong positive immunoreactivity in the cytoplasm of the neoplastic cells (×200). (C) Tumor cells also demonstrate diffuse strong cytoplasmic positive inmmunostaining for CD34 (×200).

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