ABSTRACT
AIMS: The histopathological, immunohistochemical and ultrastructural features of a primary 'mucin-positive' epithelial mesothelioma of the peritoneum are reported to draw attention to a potential cause of diagnostic error. METHODS AND RESULTS: Light microscopy showed an infiltrative neoplasm within the gastric wall and omentum which was composed of sheets of 'signet- ring' tumour cells and contained abundant diastase-resistant periodic acid-Schiff-positive material. Immunohistochemistry supported a mesothelial phenotype (cytokeratin AE1/3, thick membranous HBME-1, focal thrombomodulin and calretinin expression and no reactivity for carcinoembryonic antigen, Leu-M1 and Ber-EP4). Ultrastructural features showed large cells with prominent intercellular desmosomes and numerous delicate, elongated microvilli. Within intracytoplasmic neolumina, crystalloidal 'fern-like' bodies were identified with features similar to the ultrastructural appearances of hyaluronic acid crystals. Repeat histochemical analysis following hyaluronidase pretreatment revealed a significantly diminished diastase-resistant periodic acid-Schiff reaction. CONCLUSIONS: This case of primary peritoneal 'mucin-positive' epithelial mesothelioma demonstrates morphological and histochemical mimicry with diffuse gastric adenocarcinoma. A similar case has not been previously reported in the peritoneum and an awareness of the tumour (with application of suitable ancillary studies) prevents misdiagnosis and assists in potentially difficult medicolegal cases.
Subject(s)
Adenocarcinoma/diagnosis , Mesothelioma/diagnosis , Mesothelioma/metabolism , Mucins/metabolism , Peritoneal Neoplasms/diagnosis , Peritoneal Neoplasms/metabolism , Stomach Neoplasms/diagnosis , Adenocarcinoma/pathology , Biomarkers , Diagnosis, Differential , Fatal Outcome , Humans , Immunohistochemistry , Male , Mesothelioma/pathology , Mesothelioma/ultrastructure , Middle Aged , Peritoneal Neoplasms/pathology , Peritoneal Neoplasms/ultrastructure , Stomach Neoplasms/pathologyABSTRACT
Giant cell tumours of bone are most commonly found in the epiphyses of weight-bearing long bones. They are rarely found in the head and neck and only 17 cases involving the laryngeal framework have been reported. To date, there have been no reports of a giant cell tumour arising from the hyoid bone. We present such a case which presented as a lump overlying the greater cornu of the hyoid, review the literature and discuss the management of this locally aggressive tumour.
Subject(s)
Bone Neoplasms/pathology , Giant Cell Tumor of Bone/pathology , Hyoid Bone , Adult , Bone Neoplasms/surgery , Female , Giant Cell Tumor of Bone/surgery , HumansABSTRACT
A case of giant cell tumour of the pancreas has been studied. The light microscopical appearance of the tumour is indistinguishable from osteoclastoma of bone. Electron microscopy of the tumour shows many typical desmosomes between stromal cells. This is strong evidence of its epithelial nature. The cytoplasm of both the osteoclast-like giant cells and stromal cells contain abundant rough endoplasmic reticulum, many with dilated cisternae containing prominent dense granules. There are also some larger homogeneous granules, some of them electron-dense, in the cytoplasm of the cells. These findings when compared with the features of other cases of giant cell tumour of the pancreas studied by electron microscopy support the view that this epithelial tumour is of acinar origin.
