[822] Pseudoangiomatous Stromal Hyperplasia (PASH) of Prostatic Stroma Is Immunohistochemically Similar to Mammary PASH

Nyasha O Bullock, Richard Cartun, Richard Muller, Andrew Ricci, Jr.. Hartford Hospital, Hartford, CT

Background: Spindle cell proliferations derived from specialized prostate stroma include hyperplastic nodules, stromal tumors of uncertain malignant potential and stromal sarcomas. Some hyperplastic stromal nodules bear a striking resemblance to pseudoangiomatous stromal hyperplasia (PASH) of the breast. The current study further explores this histologic similarity.
Design: Our institution's Surgical Pathology database was queried for cases of prostate core biopsies (from June 2010 – May 2012) that specifically noted “stromal hyperplasia” in the diagnostic text field. A total of 13 cases, upon histologic review, showed features of mammary-like PASH. These cases were studied by immunohistochemistry (IHC) for CD34, desmin and hormone receptor (ER/PR) expression with antibodies known to react with mammary PASH.
Results: All 13 cases showed histologic features resembling mammary PASH, usually restricted to a portion of the core volume. Delicate inter-anastomosing cords of spindle cells with scant cytoplasm simulated blood vessels, but contained no erythrocytes. IHC studies showed CD34 positivity in 12/13 cases and ER & PR were positive in 11/13 & 13/13, respectively. Desmin was generally positive, however, in contrast to mammary PASH where smooth muscle tissue is sparse, the dense fibromuscular component in native prostate stroma confounded IHC interpretation.
Conclusions: PASH-like proliferations of the prostate, as illustrated here, resemble the lesion coined by Rosen as “pseudoangiomatous hyperplasia of mammary stroma”. Subsequent to its initial description it was found that mammary PASH frequently exhibited hormone receptor positivity, particularly PR. This study presents histologic and IHC data that formally characterize this prostate stromal proliferation and indeed supports the concept of prostatic PASH as closely analogous to mammary PASH.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 153, Wednesday Afternoon

 

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