Pancreatic polypeptide-immunoreactive gallbladder carcinoid tumor

Electron Microscopic Study Using Formalin-fixed, Paraffin-embedded Material, with Special Reference to Observation of Microbial Organisms and Endocrine Granules

In the diagnostic pathology practice, specimens for electron microscopy (EM) are not necessarily handled and fixed under the ideal condition. In the present article, the author describes ultrastructural study using formalin-fixed and/or paraffin-embedded material. The fine morphologic preservation is often acceptable, particularly when small cubes are dug out of paraffin blocks. Particulate structures such as neuroendocrine granules and microbes are consistently observed even using paraffin sections. Paraffin sections signalized with silver particles in Grimelius and Grocott stains or diaminobenzidine products in immunostaining and in situ hybridization are applicable to EM evaluation by using a pre-embedding sequence. The practical merit includes the targeted approach: highly accurate sampling from focal lesions can be achieved for EM analysis, after observing hematoxylin and eosin-stained or specific-signalized paraffin-sections. This allows us pathologists a convenient and practical way for identifying focally infected pathogens, as well as a retrospective ultrastructural analysis of rare lesions long kept as a form of paraffin blocks.

Carcinoid tumor of the gallbladder: report of two cases

We report two cases of carcinoid tumor of the gallbladder. Case 1 was a 59-year-old woman who presented with epigastric pain. Abdominal ultrasonography and computed tomography (CT) revealed a 16 mm polypoid lesion in the neck of the gallbladder. Tumor markers were within normal limits. Open cholecystectomy was performed with a preoperative diagnosis of early cancer of the gallbladder. Case 2 was a 45-year-old man. A polyp in the gallbladder was incidentally detected on annual checkup. Ultrasound and CT showed an 18 mm protruding lesion in the neck of the gallbladder. Laparoscopic cholecystectomy was performed and the tumor diagnosed as a carcinoid tumor based on the findings of funicular and tubular cells in the lamina propria mucosa, homogeneous nuclei, basophilic cytoplasm, and positive staining with chromogranin A and synaptophysin. The postoperative course of both patients was uneventful, with no recurrence at 44 and 41 months after surgery. In this literature review of 39 cases, classical carcinoid of the gallbladder has a favorable postoperative outcome. Of cases reviewed, 60% are located in the neck of the gallbladder and 50% have a polypoid shape.