[Pathogen identification of 10 suspected cases of sparganosis mansoni].

OBJECTIVE: To diagnose 10 cases of clinically suspected cases of sparganosis mansoni by pathogen identification. METHODS: In the period from August 2009 to August 2011, 10 biopsy specimens were obtained from 10 patients of four hospitals to identify the pathogen. Among the 10 cases, 4 cases showed abdominal subcutaneous mass, 3 showed eyelid swelling, 1 displayed brain lesions, 1 showed pulmonary mass, and 1 showed pleural effusion. There was one parasite each from three patients with eyelid swelling, and one patient with abdominal subcutaneous mass, which were observed by naked eye and microscope morphologically and histologically. Specimens from other six cases were examined by microscope after paraffin embedding, sectioning, and HE staining. For further identification, the parasite biopsy tissue specimens were detected by immunohistochemistry with Sparganum mansoni-immunized rabbit serum as the primary antibody. RESULTS: Three intact worms, from three patients with eyelid swelling, showed typical S. mansoni morphological characteristics. One residue parasite from the abdominal subcutaneous mass showed network structures and full of calcareous corpuscles in the body under microscope same as that of S. mansoni. The histological structure in three of the six sections showed typically the body wall with folds, which was dense, thick and deeply eosine stained, part of the tegument outside was covered by micro-hairs. In the worm body there was net-like loose structure and calcareous corpuscles without cavity. The structure of the other three worm sections was atypical. The six worm sections were positive by immunohistochemical detection. CONCLUSION: The 10 clinically suspected cases are diagnosed as sparganosis mansoni.

Pathological differential diagnosis of solid-pseudopapillary neoplasm and endocrine tumors of the pancreas.

AIM: To investigate differential points of solid-pseudopapillary neoplasm (SPN) of the pancreas and pancreatic endocrine tumor (PET). METHODS: Ten cases of SPN and fourteen cases of PET were studied in this retrospective study. Clinical and pathologic features, immunostaining reactions and beta-catenin gene mutations were analyzed. RESULTS: The mean age of SPN patients was 25.6 years and these patients had no specific symptoms. The mean diameter of the tumors was 11.0 cm, 9/10 cases were cystic or a mixture of solid and cystic structures, and there was hemorrhage and necrosis on the cut surface in 8/10 (80%) cases. Characteristic pseudopapillary structure and discohesive appearance of the neoplastic cells were observed in all 10 (100%) cases. The results of immunostaining showed that nuclear expression of beta-catenin and loss of E-cadherin in all the cases, was only seen in SPN. Molecular studies discovered that 9/10 (90%) cases harbored a point mutation of exon 3 in beta-catenin gene. On the other hand, the mean age of PET patients was 43.1 years. Eight of 14 cases presented with symptoms caused by hypoglycemia, and the other 6 cases presented with symptoms similar to those of SPN. The mean size of the tumors was 2.9 cm, most of the tumors were solid, only 3/14 (21%) were a mixture of solid and cystic structures, and macroscopic hemorrhage and necrosis were much less common (3/14, 21%). Histologically, tumor cells were arranged in trabecular, acinar or solid patterns and demonstrated no pseudopapillary structure and discohesive appearance in all 14 (100%) cases. The results of immunostaining and mutation detection were completely different with SPN that membrane and cytoplastic expression of beta-catenin without loss of E-cadherin, as well as no mutation in beta-catenin gene in all the cases. CONCLUSION: Both macroscopic and microscopic features of SPN are quite characteristic. It is not difficult to distinguish it from PET. If necessary, immunostaining of beta-catenin and E-cadherin is quite helpful to make the differential diagnosis.