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Biomedical subjects

N Weidner

Publications and source records attributed to N Weidner.

150 records · Page 9Linked to original sources
PubMedDate not supplied

Solitary fibrous tumor of the mediastinum.

A 62-year-old woman presented with an asymptomatic anterior mediastinal mass. Clinically considered to be a thymoma, the tumor was solid, firm, and composed of hypocellular dense collagen and cytologically bland, spindled fibroblastlike cells growing in a patternless pattern. There was no apparent connection to pleura or pericardium, yet the clinicopathologic features clearly fit with solitary fibrous tumor (SFT) of mediastinum. SFTs occur most commonly in pleura but have been reported in other locations, including the mediastinum, where aggressive behavior has been more common when these tumors are compared to those occurring in pleura. Although it is difficult to predict behavior for all cases of SFT occurring in the mediastinum by cytologic features alone, morphologic criteria for benign and malignant forms have been described. Roughly half the malignant forms will progress, yet the single most important indicator of clinical outcome is whether the tumor can be initially totally excised.

Diagnosis, Differential↗
PubMedDate not supplied

Malignant mesothelioma of peritoneum.

A 57-year-old man with malaise, ascites, and abdominal pain was found to have a peritoneum studied with numerous, small nodular tumor masses. Light microscopy revealed an anaplastic malignant tumor of uncertain differentiation. Mucin stains were negative. Electron microscopy revealed pleomorphic tumor cells with diffusely distributed cytoplasmic tonofilaments and well-developed true desmosomes. No long, thin, branching microvilli were present, yet tumor cells were strongly positive for both callus keratin (polyclonal) and monoclonal cytokeratin (AE1/3) in a diffuse cytoplasmic distribution (a pattern corresponding to the diffuse cytoplasmic tonofilaments). Tumor cells were negative for Leu-M1 and carcinoembryonic antigen. The findings were most consistent with malignant mesothelioma, and additional questioning, after tissue diagnosis, revealed a work history of asbestos exposure.

Cell Transformation, Neoplastic↗
PubMedDate not supplied

Pulmonary adenocarcinoma with intestinal-type differentiation.

A 44-year-old woman with a long history of smoking presented with a single lung mass detected on routine chest radiographs. There were no other known primary tumors. Light microscopy showed a mucin-producing adenocarcinoma of bronchioloalveolar type. Furthermore, no gastrointestinal primary has been discovered 18 months after discovery of the lung tumor. Electron microscopy revealed that tumor cells had microvilli containing abundant microfilamentous, dense-core rootlets that showed long extensions into apical cytoplasm. The microvilli were capped by numerous glycocalyceal bodies. These findings are similar to the ultrastructural features previously described as being specific for gastrointestinal adenocarcinomas metastatic to lung. The current case, however, suggests that the findings of glycocalyceal bodies and microvillous dense-core rootlets are not helpful in distinguishing between primary and metastatic lung adenocarcinomas.

Adenocarcinoma↗
PubMedDate not supplied

Plexiform soft tissue tumor composed predominantly of perineurial fibroblasts (perineurioma).

A 15-year-old girl presented with a small, indolent mass near the knee joint. Light microscopy revealed a peculiar myxoid plexiform tumor composed of cytologically bland cells. Interpretation of the initial biopsy material was controversial. Subsequent immunohistochemical studies revealed tumor cells to be strongly reactive for epithelial membrane antigen (EMA) and negative for S-100 protein. Ultrastructural studies revealed tumor cells with long, thin, bipolar cell processes and discontinuous basal laminae. They had no epithelial or histiocytoid features. Admixed among the tumor cells were Schwann cells, but they represented a rare and scattered component of the overall cell population. These features are most consistent with a so-called perineurioma and contrast with those of plexiform neurofibroma and traumatic neuroma (two lesions strongly positive for S-100 protein and showing a distinctive EMA immunoreactivity pattern with focal peripheral staining of neural bundles).

Adolescent↗
PubMedDate not supplied

Epithelioid monophasic synovial sarcoma.

A 47-year-old man presented with a soft tissue mass of the distal right thigh near the knee. The tumor was highly vascular with epithelioid tumor cells growing in a peritheliomatous pattern, suggesting a soft tissue glomus tumor. Yet many tumor cells contained hemosiderin pigment and formed papillary structures suggestive of pigmented villonodular synovitis. Tumor cells were cytologically bland, and there was minimal mitotic activity. The tumor cells were strongly immunoreactive for cytokeratin, however, and contained true desmosomes, gland lumina, microvilli, tonofilaments, and well-developed basal lamina. These findings plus the absence perinuclear aggregates of intermediate filaments rule out malignant rhabdoid tumor and epithelioid sarcoma. Also, magnetic resonance imaging revealed no other lesions to suggest metastatic carcinoma. Thus this tumor appears to be a predominantly epithelioid form of monophasic synovial sarcoma. Recognition of this variant of synovial sarcoma is important for prognostication and therapeutic decision making because some studies indicate that this variant of synovial sarcoma follows a relatively benign clinical course.

Humans↗