Abstract
Introduction/Objective
Mesenteric cysts are rare intra-abdominal lesions in adults. However, with the advanced imaging techniques and laparoscopic techniques, they are more often being identified and resected when clinically significant. There is a lack of detailed information in histopathology (except as case reports) since mesentery is generally neglected in our organ-based textbooks. The aim of our study is to highlight the importance of identifying and classifying mesenteric cystic lesions; they are not all that simple.
Methods
We performed a retrospective search on all mesenteric cysts submitted as excisions in our electronic database from 2013-2019. We classified them as per the de Perrot (PMID: 11053936) classification with modification.
Results
Our search showed: A. Lymphatic origin-11 (lymphangioma-10, Lymphangioma hamartomatous-1, associated with LAM-0), B. Mesothelial origin-68 (Benign mesothelial cysts-57, multilocular mesothelial cyst-11), C. Enteric origin- 3, D. Urogenital origin (Urachal cyst, mullerian inclusion cyst)-9, E. Mature cystic teratom-2, F. Pseudocyst-12, G. Epithelial cyst (not urogenital)- 11 (a/w LAMN-3, MCN-4, Mucinous cystadenoma-4), H. Associated with carcinoma-2.
Case illustration: A 61-year-old male presented with worsening dysphagia, emesis and hiccups. A CT scan showed a 21.2 cm cystic mass with at least one septation (Fig 1). The cyst was resected. On gross pathological examination, the cyst measured 18 cm in greatest dimension with a thick, rough, tan-brown capsule. Microscopic examination showed a fibrous capsule, and cyst wall composed of numerous lymphatic vessels (CD31 positive) and prominent smooth muscle proliferation (Desmin positive). Scattered lymphoid aggregates were also present throughout the cyst wall. No definite epithelial lining was identified and was suspected to have been denuded. HMB-45 immunostain was negative, ruling out association with LAM. The final diagnosis of a Lymphangiomyoma, hamartomatous was rendered.
Conclusion
Though most of the mesenteric cysts are benign, some of them are significantly important such as Lymphangiomyoma (esp secondary to LAM), MCN, those associated with LAMN etc. and identifying and differentiating from their mimics has distinct clinical implications.
Cloning and analysis of a Trichinella pseudospiralis muscle larva secreted serine protease gene
