Atypical carcinoid tumor of the lung with amyloid stroma.

Atypical carcinoid tumor of the lung with amyloid stroma seen in a 43-year-old woman is reported. The 47 x 45 x 33 mm tumor, located at the periphery of the S8 segment of the resected left lower lobe, revealed Dylon-positive amyloid deposition in the stroma. The argyrophilic tumor cells with occasional mitoses and focal venous involvement predominantly showed immunoreactivity of cytokeratin, neuron-specific enolase, cystatin C, chromogranin A, calcitonin and neuropeptide Y (NPY). Fewer cells were immunoreactive for calcitonin gene-related peptide (CGRP), the alpha-subunit of human chorionic gonadotropin, gastrin-releasing peptide, serotonin, methionine-enkephalin and gastrin. Immunoreactive CGRP or NPY were co-localized in calcitonin-positive cells. The amyloid substance was positively labeled only for CGRP. Immunostaining for amylin, a polypeptide isolated from insular amyloid in type II diabetes mellitus or insulinoma showing a 50% homology with CGRP, was negative. The specificity of immunostaining for calcitonin, CGRP and amylin was confirmed by immunoabsorption tests using synthetic human antigens. Immunoelectron microscopic studies disclosed peptide localization in neurosecretory-type granules and CGRP immunoreactivity in extracellular amyloid fibrils. This is the first report describing CGRP as a component of amyloid of endocrine origin.     

Bronchial carcinoid tumor mimicking acinic cell tumor

A rare case of carcinoid tumor mimicking an acinic cell tumor is presented. A bicameral tumor measuring 8 x 6 mm in size was recognized in the right lung (B5bi) upon gross examination. Microscopically, the tumor consisted of basophilic polygonal cells forming an acinar pattern. Ultrastructurally, the majority of tumor cells had large membrane-bound cytoplasmic granules, measuring about 600 nm in diameter, which were similar to secretary granules of serous acinar cells (zymogen granules). These findings suggested that the tumor might be an acinic cell tumor originating from the bronchial gland. However, tumor cells were shown to be negative for periodic and Schiff (PAS) stain or lactoferrin, lysozyme and amylase immunohistochemically. On the other hand, they were shown to be argyrophilic by Grimelius stain and showed immunohistochemically positive reaction for serotonin, suggesting that the granules were neurosecretory granules and not zymogen granules. Based on these findings, we concluded that this tumor was an unusual variant of carcinoid tumor mimicking acinic cell tumor. Although carcinoid tumor has a wide histological spectrum, there has been no reported case, to our knowledge, of acinic cell tumor-like carcinoid tumor.     

Bronchial carcinoid tumor with crystalloid cytoplasmic inclusions.

We report a bronchial carcinoid tumor with distinctive, cytoplasmic, rod-shaped crystalloid inclusions that were visible by light microscopy. These cytoplasmic structures were immunoreactive with antibodies against chromogranin A and synaptophysin in paraffin-embedded tissue. Ultrastructural studies showed them to be paracrystalline in nature and located within lysosomes. This case highlights an interesting, and potentially confusing, histologic manifestation in an otherwise typical bronchial carcinoid tumor.     

Bronchial neuroendocrine (carcinoid) tumor causing unilateral left-sided carcinoid heart disease

Summary A female patient suffering from a bronchial neuroendocrine tumor with unilateral leftsided carcinoid heart disease is reported. Repeated x-ray films of the chest showed a slowly growing lung tumor in the left lower lobe. The patient refused any diagnostic or therapeutic procedure to define the type of the tumor. During the follow-up of 24 years she developed severe mitral and moderate to severe aortic insufficiency, both invasively quantified by thermodilution techniques. During surgery for double valve replacement the patient died from left ventricular heart failure. Necropsy revealed the typical pattern of a bronchial neuroendocrine tumor without metastases. Examination of the heart disclosed the characteristic deposits of fibrous tissue on the cusps of both the mitral and the aortic valves whereas the right heart showed no abnormalities. Review of the literature suggests the unilateral left-sided carcinoid heart disease to be a very rare finding, its pathogenesis remains to be elucidated.     

Thymic carcinoid with mucinous stroma: a rare variant of carcinoid with an aggressive clinical course

One variant of thymic carcinoid has prominent mucinous stroma first reported in 1995. We describe such a case characterized by abundant stromal mucin resulting in a histologic picture resembling of metastatic mucinous adenocarcinoma. This variant seems to behave in an aggressive fashion and should be under the differential diagnoses of mediastinal neoplasm with prominent mucin production.     

Bronchial carcinoid appearing as a breast mass

Carcinoid tumors of the breast are extremely rare. We studied what is to our knowledge the second case of an extramammary carcinoid presenting initially as a breast mass. Varying degrees of ribbon, trabecular, acinar, and insular patterns were present in the primary bronchial tumor and in several secondary deposits, including the initial breast lesion. The cells were argyrophilic and contained round and membrane-bound electron-dense granules. Estrogen and progesterone receptors were present in a cerebral metastasis. Polypeptide hormones and 5-hydroxytryptamine were not detected by immunocytochemistry.     

Bronchial carcinoid with paranuclear fibrillary inclusions related to cytokeratins and vimentin

Summary A bronchial carcinoid with globular intracytoplasmic inclusions is reported. The inclusions stain brown with Grimelius silver impregnation and some show distinct immunoreactivity for chromogranin A. Tumour cells stain positively with antisera to neuron specific enolase, chromogranin A and not with antisera against ACTH, somatostatin or S-100 protein. The cells show distinct immunoreactivity for cytokeratins and vimentin, which is particularly intense in the intracytoplasmic inclusions. Desmin and glial fibrillary acidic protein are absent. Ultrastructural analysis reveals that the inclusions are composed of aggregates of filaments of 8–10 nm of diameter, intrapping a few neurosecretory granules. Immunohistochemical and ultrastructural data support the hypothesis that the inclusions are composed of intermediate filaments, whose metabolism and synthesis have somehow been deranged.     

Primary hepatic carcinoid tumor

A case of primary carcinoid tumor arising in the liver of a 69 year old woman with no endocrine symptoms is reported. Histopathologically, the tumor was diagnosed initially as a hepatocellular carcinoma in the biopsy specimen, and was shown subsequently to be a carcinoid tumor, demonstrating diffuse positive staining with Grimelius method. Mucin stained with periodic acid-Schiff (PAS), alcian-blue, and mucicar-mine, and was shown partially in the glandular structures. Immunohistochemically, most of the tumor cells stained positively for chromogranin-A, epithelial membrane antigen (EMA) and neuron specific enolase (NSE). Ultrastructural examination revealed electron-dense core granules, measuring 40-120 nm in diameter in some of the tumor cells. Intensive and careful searches pre- and post-operatively revealed no other primary source of tumor other than the liver. The patient was reported well with no symptoms 3¹/₂ years after the operation.     

Disseminated rectal carcinoid tumor with production of immunoreactive motilin

This report presents a patient with a rectal carcinoid tumor of small size ( 14 mm in diameter), with typical growth pattern, localized in the mucosa. Despite these microscopically good prognostic features the patient died from metastatic disease 30 months later. The tumor had an unusual hormone profile with main secretion of immunoreactive motilin and serotonin. Immunocytochemically these substances were localized in separate tumor cell populations; the majority of tumor cells were motilin-immunoreactive and a minority were serotonin-immunoreactive. The patient was first treated interventionally by hepatic arterial embolizations and later medically with octreotide. The treatment resulted in long periods of good palliation related to reduced levels of tumor markers and weight gain. The plasma concentrations of motilin were analyzed with a N-terminal-specific assay before and during treatment.     

A carcinoid tumor of the stomach with features of a midgut tumor

This report is, to our knowledge, the first of a gastric carcinoid tumor that, by electron microscopy, revealed pleomorphic neurosecretory granules similar to those found in carcinoid tumors arising from the midgut. On the basis of silver staining, this lesion would be classified as an argentaffin and argyrophil carcinoid tumor, of the type usually associated with midgut derivation. Immunostaining showed the presence of serotonin granules, and there was clinical evidence of intraoperative hyperserotoninemia. The lesion is believed to have arisen from foci of complete intestinal metaplasia, many of which were present in proximity to the site of the lesion and elsewhere in the stomach.     

Bronchial carcinoid accompanied by thyroid adenomas and adrenal adenomas.

A large tumor massively occupying the left pleural cavity had the findings of both typical carcinoid and onococytoma which were thought to be of bronchogenic origin. The ultrastructural observation of the tumor revealed a mixture of rod-shaped granules in addition to usual round neurosecretory ones. In the nuclei of dark cells of the oncocytoma, a latticed or hatched structure was detected. Besides two adenomas and hyperplastic foci of large acidophilic cells in the thyroid, a black adenoma and cortical adenoma in the adrenal gland, were detected. Moreover, there was an ectopic adrenal gland in the retroperitoneum. Briefly it was suggested that the bronchial carcinoid presented may be related to multiple endocrine adenomatosis.