No abstract

Prevalences of diverticulum and low-grade mucinous neoplasm (LGMN) were reported as 0.04-2% and less than 1% in the appendix. In this study, the frequency of diverticulum in LGMN cases, the relationship between diverticula and periappendicular mucin, and the possible role of diverticula in pseudomyxoma peritonei pathogenesis were researched. Through systematic review and targeted search, 38 LGMN and 96 diverticula were identified, frequencies and relationship between diverticulum and LGMN were analysed. Diverticulum and LGMN were determined in 4.8% and 1.04%, respectively, of 1922 appendectomy materials specifically grossed by the same pathologist. The prevalence of diverticulum was higher in our study than literature. The difference may be due to detailed macroscopic examination. Diverticulum was detected in 60% of LGMN cases. The rate of diverticulum was found to be significantly higher in LGMNs than non-neoplastic diverticulum (p < 0.001). Periappendicular mucin deposition was significantly more frequent in LGMN cases with diverticulum than in other groups (p < 0.05). Follow-ups were available in 18 patients; none of them had mucin deposition in the peritoneal cavity. We detected that periappendicular mucin was highly associated with diverticula in LGMN cases. Periappendicular acellular mucin deposition may not give rise to pseudomyxoma peritonei. We may think that mucin could move out of the appendix through the diverticulum rather than neoplastic spread in some of these cases.

No abstract

Intravascular/intralymphatic histiocytosis (IV/ILH) is a rare, reactive cutaneous condition, with uncertain pathogenesis. It may be associated with various inflammatory and neoplastic diseases. Although the clinical presentation is various, the biopsies reveal dilated vessels, mostly lymphatics, containing aggregates of histiocytes within their lumina. We described 3 cases of IV/ILH with different clinical presentations. In the first case, the patient presented with lymphedema in the genital region without any underlying disease. However, the second and third cases had reticular erythematous skin lesions. The second case had common variable immunodeficiency disease, rheumatoid arthritis, inflammatory bowel disease, and a history of a lymphoproliferative lesion. The third case had metal prostheses at both his right and left knees. In all these 3 cases, histopathologic and immunohistochemical findings were similar to each other and to those cases reported in the literature. In addition, the third case was admixed with reactive angioendotheliomatosis. In the second case, the endothelium of the ectatic vessels expressed CD31 and CD34, but not D2-40/podoplanin, pointing out that these vessels were blood vessels rather than lymphatics, differing from the other 2 cases. In conclusion, we believe, the most convincing statement about IV/ILH is that it is not a distinct clinicopathologic entity, but a histopathologic feature found as a part of a constellation of inflammatory changes or many other conditions.