Malignant epithelioid mesothelioma of the pleura with hyaline globules.

Sir: Granulomas both of the foreign body and delayed hypersensitivity (immune) type are usually part of tissue-based inflammatory processes. In some diseases such as sarcoidosis, which are characterized by granuloma formation, an association with lymphatic vessels does not appear to be a feature. In Crohn’s disease, it is a frequent occurrence. In addition, granulomatous lymphangitis of the scrotum and penis, granulomatous cheilitis and Melkerson–Rosenthal syndrome are also associated with periand intralymphatic granulomas. These latter conditions are considered by some to be a forme fruste of Crohn’s disease. Migratory, noninflammatory intralymphatic granulomas are a separate and presumably rare entity and the statement that ‘granulomas are not static’ would appear to be true in more ways than one. Examination of the gastrectomy specimen, from a 70-year-old male with a 100 · 70-mm infiltrating moderately differentiated adenocarcinoma, was found to have 13 of 23 lesser curvature nodes and 32 of 45 greater curvature nodes replaced by metastatic carcinoma. One uninvolved lymph node contained a very poorly formed granuloma with, in one of the adjacent afferent lymphatic vessels, a small and apparently ‘in transit’ well-formed, non-caseating granuloma (Figures 1 and 2). Granulomas were not present in the stroma of the carcinoma. It would seem that granulomas should have the property of exhibiting migratory capabilities due to the wealth of cytokines involved in their initiation and maintenance. However, the presence of a granuloma within a lymphatic channel as an isolated event is an extremely unusual occurrence. In cancer, granulomas are rarely found within the stroma but somewhat less commonly present within the draining lymph nodes. It is possible that this occasional process is initiated within the stroma as an immune surveillance response but retreats to the lymph nodes if this response is overwhelmed. Alternatively, and probably more likely, it may represent transport of a displaced tissue granuloma similar to the recently discussed mechanism of dislodgement and transportation of benign epithelium to lymph nodes.