Inverted variant of urothelial carcinoma of the urinary bladder: a report of three cases and a proposal for a new clinicopathologic entity

Inverted urothelial carcinoma (UC) without papillary areas is very rare; only 31 cases of three papers have been reported. The author herein reports three additional cases, and proposes the term “inverted variant” (IV) of UC. The materials were 3 cases of IV of UC, 5 cases of inverted papilloma (IP), and two cases of nested variant (NV) of UC. The three cases of IV of UC consisted of 56-year-old woman, 63-year-old man, and 78-year-old man. Presenting symptoms were hematuria in all cases. The cystoscopic findings were elevated tumors without papillary proliferations in all cases. The treatment was transurethral tumor resection (TUR-BT) in all cases. The sizes was 0.6 cm, 0.5 cm, and 3 cm. Microscopically, IV of UC showed inverted growth of atypical cells without papillary proliferations. Compared to IP, the inverted growth pattern was similar, but cytological atypia and thick trabeculae were noted in IV of UP while they were absent in IP. Compared to NV of UC, the growth pattern is different; NV of UC showed nested and vague tubular pattern. The cellular atypia is more pronounced in IV of UC than NV of UC. Immunohistochemically, p53 expression was seen in all the cases of IV of UC and in all the cases of NV of UC, while p53 expression was negative in all the cases of IP. Ki-67 labeling index was 25, 30 and 40% in IV of UC, 15 and 30% in NV of UC, and 3, 5, 6, 7, 9% in IP. Invasive features were seen in 1 case of IV of UC and 2 cases of NV of UC. In all cases of IV of UC, IP, and NV of UC, the TUR-BT, but one case of IV of UC, showed no recurrence after TUR-BT, while one case of IV of UC showed a recurrence. In conclusion, the IV and UC were structurally and cytologically very different from the NV of UC. The IV of UC was structurally similar to IP, but cellular atypia and thickened trabeculae were seen in IV and UC. p53 expression and Ki-67 labeling status were entirely different between in IV of UC and IP. The author proposes the term of IV of UC as a new clinicopathological entity.     

Histopathologic study of the rectum in 1,438 consecutive rectal specimens in a single Japanese hospital: I. benign lesions

The author investigated histopathology of 1,438 consecutive rectal specimens in the last 10 years of our pathology laboratory in Japan. A computer review of pathologic reports was done. Observations of pathologic slides were performed, when appropriate. The rectal specimens were composed of 1,022 benign lesions and 416 malignant lesions. The 1,022 benign lesions were composed non-specific proctitis (n=460, 45%), adenoma (n=248, 24%), ulcerative colitis (n=98, 10%), hyperplastic polyp (n=54, 5%), carcinoma in adenoma (n=40, 4%), rectal ulcer (n=37, 4%), serrated adenoma (n=24, 2%), hyperplastic nodule (n=21, 2%), Crohn’s disease (n=9, 1%), ischemic proctitis (n=8, 0.8%), mucosal prolapse syndrome (n=7, 0.6%), juvenile polyp (n=6, 0.6%), lymphoid hyperplasia (n=5, 0.5%), lipoma (n=4, 0.4%) and amebic dysentery (n=2, 0.2%), and mature cystic teratoma (n=1, 0.1%). In this article, histopathological features of these benign lesions were described in details. In particular, adenomas were classified into adenomas with mild, moderate, and severe atypia, serrated adenoma, and carcinoma in adenoma. The later are mainly seen in large adenoma with severe atypia. Ulcerative colitis was characterized by continuous lesion, crypt abscess, abnormal branching, and deletion of goblet cells. Crohn’s disease was characterized by transmural inflammation and epithelioid granulomas. Ischemic colitis was characterized by ischemic necrotic changes and pseudomembrane formation. Mucosal prolapse syndrome was characterized by abnormal muscle in the mucosa (fibromuscular obliterance). Juvenile polyp was characterized by abnormal dilations of the crypts. Lymphoid hyperplasia must be differentiated from MALT lymphoma. Lipoma was ordinary lipoma without lipoblasts. Amebic dysentery was characterized by ulcer and presence of histiocyte-like entamoeba histolitica. Mature cystic teratoma was characterized by hairs and other elements of skin and mesodermal and endodermal components.     

Changes in wall shear stress magnitude after aneurysm rupture

Computational fluid dynamics (CFD) studies on cerebral aneurysms have attempted to identify surrogate hemodynamic parameters to predict rupture risk. We present a case of bilateral mirror image aneurysms, one of which ruptured soon after imaging. Wall shear stress values of the ruptured aneurysm changed by 20–30 % after rupture because of change in the aneurysm shape. Findings from our case suggest that CFD studies comparing unruptured and ruptured aneurysms may not yield valid estimation on aneurysm rupture risk because of changes in aneurysm shape after rupture. Changes in aneurysm shape after rupture should be considered in CFD research.     

Interaction of Necl‐4/CADM4 with ErbB3 and integrin α6β4 and inhibition of ErbB2/ErbB3 signaling and hemidesmosome disassembly

Nectin‐like molecule 4 (Necl‐4)/CADM4, a transmembrane cell–cell adhesion molecule with three Ig‐like domains, was shown to serve as a tumor suppressor, but its mode of action has not been elucidated. In this study, we showed that Necl‐4 interacted in cis with ErbB3 through their extracellular regions, recruited PTPN13 and inhibited the heregulin‐induced activation of the ErbB2/ErbB3 signaling. In addition, we extended our previous finding that Necl‐4 interacts in cis with integrin α₆β₄ through their extracellular regions and found that Necl‐4 inhibited the phorbol ester‐induced disassembly of hemidesmosomes. These results indicate that Necl‐4 serves as a tumor suppressor by inhibiting the ErbB2/ErbB3 signaling and hemidesmosome disassembly.     

Three adult cases with Corynebacterium propinquum respiratory infections in a community hospital

Corynebacterium propinquum, which is included in Corynebacterium group ANF-3, exists as a commensal in the oral flora. This organism has not yet been fully recognized as a respiratory pathogen. We previously reported that the first case with respiratory infection caused by C. propinquum. On the other hand, Corynebacterium pseudodiphtheriticum is recognized as a causative organism in respiratory infections. Recently we experienced two cases with C. propinquum respiratory infections in our hospital. Three types of the onset such as a community-acquired infection, a hospital-acquired infection, and a nursing home acquired infections were observed. Our analysis indicated that gram staining of the purulent sputum is an essential tool to evaluate whether C. propinquum is a respiratory pathogen or not, because this organism is a commensal bacteria.