In Sook Seo

Oncocytic neoplasms of salivary glands: a report of fifteen cases including two malignant oncocytomas.

Fifteen oncocytic (oxyphilic granular cell) neoplasms of the salivary glands collected from three large university medical centers are presented. The histologic and ultrastructural criteria that characterize oncocytes are presented and electron micrographs of two of our cases are discussed. Included in the series are 10 benign oncocytomas, two malignant oncocytomas and three benign, oncocytic pleomorphic adenomas. The clinical and pathologic features of benign oncocytomas are reviewed, with special attention to the variety of gross and microscopic changes present. The literature on malignant oncocytomas is critically reviewed, diagnostic criteria are evaluated, and a unique case is discussed in detail. Reference is made to a group of neoplasms that we designate as benign, locally aggressive oncocytomas. The problem of differential diagnosis between oncocytoma and benign, oncocytic pleomorphic adenoma is considered.

Goblet cell carcinoid of appendix: ultrastructural features and histogenetic aspects.

Light and electron microscopic examination of a goblet cell carcinoid revealed cells with pleomorphic neurosecretory‐type granules, cells containing mucin some of which also contained these granules and less differentiated cells lacking the aforementioned features. Recent embryologic and anatomic studies of developing avian and mammalian gut, respectively, show that intestinal APUD cells are probably of endodermal origin. Therefore, mixed carcinoid tumors such as the goblet cell variant could arise in crypt base stem cells.

Multiple visceral and cutaneous granular cell tumors. Ultrastructural and immunocytochemical evidence of Schwann cell origin.

Granular cell tumor of the stomach is rare and may occur in association with similar tumors in the skin. Two such tumors were found in association with cutaneous granular cell tumors in two black females. Infiltrating carcinoma of the stomach was suspected at surgery in one case. All of the lesions were typical granular cell tumors on light microscopic examination. Ultrastructural examination showed clusters of tumor cells that were surrounded by basal laminae and axonal structures were present among the tumor cells. S‐100 protein immunoreactivity was also demonstrated in the tumor cells. These findings suggest a Schwannian origin for visceral granular cell tumors.

Pancreatic-polypeptide-producing apudoma of the liver

A large hepatic neoplasm excised from a 62–year‐old man resembled a carcinoid tumor. No endocrine syndrome was present and an alternative primary source of tumor was not found, despite an intensive search. The tumor cells were classified according to the type of electron‐dense granules present: ACTH, gastrin (G), bombesin (P), and pancreatic polypeptide (PP) type granules were identified, Immunofluorescent staining with antibodies to several polypeptide hormones detected PP‐containing tumor cells only. This rare tumor is therefore a PP‐apudoma; possibly of intrahepatic bile duct origin.

A combined morphologic and immunologic approach to the diagnosis of gastrointestinal lymphomas. I. Malignant lymphoma of the stomach (a clinicopathologic study of 22 cases)

Twenty‐two cases of primary gastric non‐Hodgkins lymphoma, which occurred over a 20‐year period, were reviewed. Eighteen tumors were studied using an immunoperoxidase method, and the presence of intracytoplasmic monoclonal immunoglobulin (Ig) in nine (50%) suggested a B‐cell origin. Four tumors (22%) contained intracytoplasmic muramidase (lysozyme), suggesting a true histiocytic origin. Five tumors (28%) did not contain immunoglobulin or muramidase. The muramidase‐positive “true histiocytic lymphoma” could not be differentiated from histiocytic lymphoma of lymphocytic origin using light microscopic examination alone. The patients with B‐cell lymphoma survived significantly longer than patients in the other two groups. The differentiation between true histiocytic lymphoma and other conditions is discussed.

Leimyosarcoma of the urinary bladder. 13 years after cyclophosphamide therapy for Hodgkin's disease

A leiomyosarcoma of the urinary bladder occurred in a 17‐year‐old boy who was treated with a total dose of 67 g cyclophosphamide over a period of 5 years for Hodgkins disease diagnosed at the age of 4. Cyclophosphamide was discontinued at the age of 9 because of gross hematuria, and intermittent hematuria recurred 8 years after (at the age of 17) the cessation of this drug. A large exophytic tumor found in the urinary bladder was diagnosed as leiomyosarcoma by light and electron microscopic studies. In addition, there were microscopic features of long‐term cyclophosphamide toxicity throughout the bladder wall.

Metastasizing atrial myxoma.

Tumors that were identical in morphology to a previously excised atrial myxoma were found in the choroid plexus and the scapula of a 46-year-old woman 8 and 10.5 years, respectively, after cardiac surgery. Ultrastructurally the scapular lesion resembled previously reported atrial myxomas. This case demonstrates that atrial myxoma is a true neoplasm capable of metastatic spread despite its slow growth and innocuous histologic appearance.

Flow Cytometric Immunophenotypic Characterization of Pediatric and Adult Minimally Differentiated Acute Myeloid Leukemia (AML-M0)

We reviewed the clinicopathologic and immunophenotypic profiles of 7 pediatric and 11 adult minimally differentiated acute myelogenous leukemias (AML-M0). We also compared and evaluated myeloperoxidase in leukemic blasts using standard cytochemical and polyclonal antibody immunohistochemical stains. No distinctive clinical findings were noted in either patient group; however, thrombocytopenia typically was more prominent in adults. Adult AML-M0 also was associated with an immature myeloid profile (CD34+, terminal deoxynucleotidyl transferase positive, CD13+, and CD33+), in contrast with pediatric AML-M0, which usually lacked terminal deoxynucleotidyl transferase or CD34 but expressed bright CD33 with weak or negative CD13. Coexpression of the T-cell-associated antigen CD7 was observed in both groups. Antibody immunohistochemical stains were more sensitive than cytochemical stains for detection of myeloperoxidase activity and a useful adjunct for establishing a diagnosis of myeloid leukemia in paraffin-embedded marrow tissues.

Clear Cell Carcinoma of the Larynx A Variant of Mucoepidermoid Carcinoma

A case of clear cell carcinoma of the larynx is presented. By light microscopy the lesion was composed mainly of sheets of clear cells, containing intracytoplasmic mucin and glycogen. Glandular lumina, tonofilaments, and desmosome-tonofilament complexes were observed on electron microscopy. The presence of these features established that this unusual neoplasm was a clear cell variant of mucoepidermoid carcinoma.

Ossifying Fibromyxoid Tumor: Modified Myoepithelial Cell Tumor? Report of Three Cases with Immunohistochemical and Electron Microscopic Studies

Ossifying fibromyxoid tumors (OFMT) are rare soft tissue tumors of uncertain histogenesis and clinical behavior. Since Enzinger, Weiss, and Liang first described 59 examples in 1989 (Am Surg Pathol. 13:817–827), approximately 150 cases have been reported. Their clinicopathologic features are fairly well characterized and their histogenesis remains unknown. Three examples of soft tissue tumors with typical histopathologic characteristics of OFMT were studied: case 1, a 43-year-old female with a 2.5-cm tumor of the back; case 2, a 56-year-old man with an 8-cm thigh mass; and case 3, an 81-year-old female with a 13.5-cm buttock tumor. For immunohistochemistry, formalin-fixed, paraffin-embedded tissue sections were stained with antibodies against cytokeratin, smooth muscle actin, desmin, vimentin, S-100 protein, EMA, and collagen type IV using standard ABC-peroxidase methods. For electron microscopy, tissue samples fixed in EM-grade buffered formalin were processed according to routine methods. Immunohistochemistry showed that the tumor cells were positive for vimentin and S-100 protein in all 3 cases. Stains for collagen type IV revealed diffusely positive staining in the stroma with a tendency for stronger staining around the cell borders in 2 out of 3 cases. Desmin was positive in one and actin was positive in one other case. By electron microscopy, tumor cells were characterized by centrally located round to oval nuclei with varying amounts of cytoplasm containing scanty cytoplasmic organelles. There were rare profiles of rough-surfaced endoplasmic reticulum (RER) and rare mitochondria with areas of condensed intermediate filaments. No tonofilaments or actin filaments were present. There were multiple short web-like processes, some of which were attached to that of neighboring cells by primitive cell junctions. In all 3 cases, lesional cells showed external lamina (EL), which was abundant in case 1, forming redundant scrolls frequently. In case 2, EL was less prominent and incomplete, and interrupted portions of EL were present only along the periphery of cell columns or nests bordering the stroma. In case 3, which behaved as a malignant tumor, the tumor cells were less differentiated spindle cells with primitive cellular features, and EL was rarely found along the short span of tumor cell borders. In this study, tumor cells in OFMT were polygonal to stellate often with multiple short cytoplasmic processes. The tumor cells were found to form cell clusters attached by primitive intercellular junctions between cytoplasmic processes forming intercellular bridges. The cell borders facing the stroma around cell clusters tended to be flat and had incomplete EL, while no EL was present along the cell borders facing the inner aspect of cell clusters. These ultrastructural findings together with immunophenotypic expression of S-100 protein presented closer resemblance to those of modified myoepithelial cells in pleomorphic adenomas of salivary glands and skin appendages rather than peripheral nerve sheath tumors. The authors conclude that these findings render more support to the hypothesis of myoepithelial histogenesis of OFMT. They also conclude that ultrastructural study not only helps accurate diagnosis, but also may aid in predicting malignant behavior by the degree of deviation from the typical examples of OFMT.