[801] The Morphology and Immunohistochemical Phenotypic Expression of Focal Prostatic Atrophy

Athanase Billis, Luciana Meirelles, Leandro LLL Freitas, Betina D Lins, Joao FL Bonfito, Larissa BE Costa, Paola H Poletto. University of Campinas (Unicamp) School of Medicine, Campinas, SP, Brazil

Background: Prostatic atrophy is one of the most frequent histologic mimics of prostate carcinoma. Inactive or active inflammation and ischemia are involved in its etiopathogenesis. Proliferative inflammatory atrophy (PIA) was proposed to designate focal simple or postatrophic hyperplasia occurring in association with inflammation and may represent a precursor lesion to high-grade prostatic intraepithelial neoplasia and, therefore, prostatic carcinoma. The atrophic luminal cells in PIA show aberrant phenotypic expression consistent with intermediate cells. We performed a detailed analysis of the morphology of focal atrophy and extended the study of immunohistochemical phenotypic expression to partial atrophy and to all subtypes of complete atrophy.
Design: We studied 120 needle prostatic biopsies showing only focal atrophy. The lesion was classified into partial and complete. The latter subtyped into simple, hyperplastic (or postatrophic hyperplasia) and sclerotic. Immunohistochemistry was performed for PSA, PAP, CK8, CK18, Cam 5.2, 34βE12, p63, CK5, CK14, AR, CD44, c-met, GSTP, CD133, α2β1 integrin, and c-myc.
Results: Partial atrophy was present in 69/120 (58.1%) biopsies; complete atrophy in 118/120(98.3%) biopsies; and, in 67/120 (55.8%) biopsies both lesions were found. In 32/120 (26.6%) biopsies partial atrophy merged with complete atrophy in the same focus as well as in the same gland. Chronic inespecific inflammation was seen only in complete atrophy. The immunohistochemical phenotypic expression of partial atrophy was similar to normal acini. The luminal cells of complete atrophy (simple, hyperplastic, or sclerotic subtypes) were PSA-/PAP-/34βE12+ consistent of an intermediate-type cell. In complete atrophy foci with or without inflammation there was overexpression of GSTP, c-met, and CD44.
Conclusions: Partial atrophy and complete atrophy are frequently found in the same biopsy. The mergence of these two lesions and the transitions in the same gland seems to favor that partial atrophy precedes complete atrophy. The absence of inflammation in partial atrophy as well as in areas of mergence between the lesions favors that chronic inespecific inflammation may be a secondary phenomenon. Aberrant phenotypic expression of luminal cells was seen in all subtypes of complete atrophy but not in partial atrophy as well as overexpression of GSTP, c-met, and CD44 was seen only in complete atrophy.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 1:00 PM

Poster Session II # 185, Monday Afternoon

 

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