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Phyllodes-like focus in prostatic hyperplasia
John D Coyne
Department of Pathology, The Royal Oldham Hospital, Oldham OL1 2JH, UK
John D Coyne,
Department of Pathology, The Royal Oldham Hospital, Oldham OL1 2JH
Source of Support: None, Conflict of Interest: None
Benign nodular prostatic hyperplasia is extremely common but an unusual variant, fibroadenoma-like prostatic hyperplasia, is uncommon. However, foci resembling phyllodes tumor have not previously been described in prostatic hyperplasia. This report highlights this occurrence and its possible association with phyllodes tumor of the prostate.
A 70-year-old man presented with urinary retention. Sequential prostate-specific antigen levels taken over a 10-month period ranged from 6.29 to 7.35 ng/mL. Microscopic examination revealed usual benign nodular and stromal prostatic hyperplasia, mixed acute and chronic inflammation, and a 3-mm focus resembling a benign phyllodes tumor. This focus showed elongated epithelial-lined clefts with several leaf-like, expanded stromal protrusions covered by glandular and basal epithelium with focal squamous metaplasia [Figure 1] and [Figure 2]. The stroma was expanded and mildly hypercellular with subepithelial condensation. Mitotic figures were not seen and there was no evidence of cytological atypia. On further sectioning, the focus cut out.
|Figure 1: Epithelial-lined clefts with several leaf-like, expanded stromal protrusions resembling phyllodes tumor|
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Benign nodular prostatic hyperplasia is extremely common. The fibroadenomatoid variant is rather less, with an apparent incidence of 1%., Nodular hyperplasia with cystic glands and foci resembling fibroadenoma can be misinterpreted as phyllodes tumor. The focus described herein was small, circumscribed, outwith a hyperplastic nodule, and fulfilled the criteria defined by Rosen for distinguishing phyllodes tumors from fibroadenomas.
Moreover, both benign and malignant phyllodes tumors (but not fibroadenomas) have been described in the prostate although their origin and histogenesis have not been well-characterized.,,
It has been suggested that the leaf-like phyllodes feature is only one of the several patterns seen in lesions termed stromal tumors of uncertain malignant potential (STUMP)., However, a number of reports contend that there are no specific criteria in this approach that offer a breakthrough in differential diagnosis. Instead, reports consider that stromal tumors of uncertain malignant potential be reserved for biopsies and that phyllodes tumor should be diagnosed on excised specimens showing appropriate features. In addition, the malignant counterpoint of STUMP with a leaf-like pattern is also termed malignant phyllodes tumor, and grading of such tumors is predictive of outcome in the short term. Of interest, epithelial squamous metaplasia occurs in 10% of breast phyllodes tumors but in only 0.3% of fibroadenomas and is postulated to be more common in benign, as opposed to malignant, prostatic phyllodes tumors. It is unlikely that phyllodes-like foci have a pathogenetic role in prostatic phyllodes and stromal tumors; nevertheless, a phyllodes variant of hyperplasia does appear to exist.
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[Figure 1], [Figure 2]