Primary proximal urethral adenocarcinoma: Case report and brief review

A PAX-8-Positive Female Urethral Adenocarcinoma, Intestinal-Type: A Case Report with Diagnostic Challenges and a Review of the Literature

Female urethral adenocarcinoma (FUA) is extremely rare. It is an aggressive malignancy, and clear cell and columnar/mucinous ("intestinal") represent the two primary histologic subtypes. Diagnosis is often delayed in patients because of their vague symptomatology; hence, they present with an advanced disease and a poor prognosis. The rarity of FUA brings challenges when determining treatment and management, and treatment guidelines for various stages are lacking. We report an intestinal-type FUA that developed from inflammation-related metaplasia in urethral diverticulum with positive paired box 8 (PAX-8) staining. In addition to intestinal-type FUA being extremely rare, this particular entity exhibiting PAX-8 positivity has not been previously described, to the author's best knowledge. The present report highlights the importance of clinical and radiological assessment as well as histomorphologic and immunophenotypic features for an accurate diagnosis of this rare and aggressive malignancy.

CR, Mauney JR. Acellular bi-layer silk fibroin scaffolds support tissue regeneration in a rabbit model of onlay urethroplasty

Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width×Length, 1×2 cm²) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to pre-operative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (α-smooth muscle actin and SM22α) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study demonstrate that bi-layer silk fibroin scaffolds represent promising biomaterials for onlay urethroplasty, capable of promoting similar degrees of tissue regeneration in comparison to conventional SIS scaffolds, but with reduced immunogenicity.