Stromal Epithelial Unit of the Prostate: A Potentially New Histological Finding in the Prostate with an Unknown Function
Kailey J Trautmann, Joseph D Kronz. St. Alphonsus Medical Center-Nampa, Nampa, ID
Background: Prostatic secretions flow through ducts until they reach the prostatic urethra. The stroma surrounding these ducts has a haphazard appearance. We have noted a unique histologic finding where the prostatic stroma is organized in a circular fashion around a central duct which appears to be draining several smaller ducts. We named this finding “stromal epithelial unit (SEU)” as its function is unknown. This is an initial descriptive study of SEU.
Design: SEU cases were collected over a 5 month period. The cases were evaluated for: Age; Location; Epithelial state of the central duct; Number of connecting ducts; Cytoplasmic and nuclear detail of central duct; Basal cells; Inflammation; Sclerosis; Epithelial state of surround glands; Peripheral vessels; stromal nuclei; Stomal nuclei intranuclear inclusions; bulging from core; PIN4 and S100 staining.
Results: 119 needle core biopsies and one RP specimen were reviewed with 22 SEUs found in 18 patients (15%). Age range was 54-76 (mean 65.5 yrs). SEU location was: 9 mid; 4 base; 3 apex; 4 Transitional and 2 Not stated. The majority of SEUs had small nuclei 17/22 (77%). 11/22 SEUs had atrophic cytoplasm and the remainder had normal cytoplasm. Basal cells were identified in 21 of 22 SEUs. Number of connecting ducts varied from 0 to 7 (Average 2). Epithelial state of surrounding ducts was normal in 17/22 (77%) cases. No SEUs had surrounding sclerosis. 68% of SEU had surrounding vessels. Stomal nuclei were round and spindled in 72%. Stromal cell intranuclear inclusions were identified in 5/22 cases (22.7%). The SEU bulged from the needle core in 36% of cases. S100 stains demonstrated small nerve staining in 79% of cases which was decreased in density as compared to surrounding non-SEU stroma. One RP SEU was identified, located just posterior to the verumontanum and was similar to biopsy SEU.
Conclusions: To our knowledge SEUs have not been previously described. SEUs appear to be a point at which multiple small ducts empty into a central duct near the verumontanum. This central duct is surrounded by a circular shaped organized stroma that has several unique features including stromal intranuclear inclusions; surrounding vessels and decreased density and size of S100 identified nerve fibers. The function of SEUs is not known and may represent an active or passive microsphincter or sensory function. It is unlikely that this may represent the earliest manifestation of sclerotic atrophy or benign prostatic hyperplasia. Further investigation is needed including detailed study of RP material.
Category: Genitourinary (including renal tumors)
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 173, Tuesday Afternoon