Noel Weidner

Phosphaturic mesenchymal tumors. A polymorphous group causing osteomalacia or rickets

Reported are the pathologic features of 17 mesenchymal tumors documented as causing osteomalacia or rickets. Although these tumors were histologically polymorphous, they were classifiable into four morphological groups. In the first group there were ten unique tumors showing mixed connective tissue features and containing variably prominent vascular and/or osteoclast‐like giant‐cell components. Tumors of this group also displayed focal microcystic changes, osseous metaplasia, and/or poorly developed cartilaginous areas. The cartilaginous areas sometimes showed considerable dystrophic calcification. With one exception, all tumors of this group occurred in soft tissue and demonstrated benign clinical behavior. The single malignant tumor originated in bone, recurred locally, and metastasized to lung. The tumors comprising the remaining three groups (six tumors) occurred in bone, demonstrated benign clinical behavior, and were grouped according to their close resemblance to tumors known to occur in bone, that is osteoblastoma‐like (four tumors), nonossifying fibroma‐like (two tumors), and ossifying fibroma‐like (one tumor).

Endoscopic biopsy is diagnostic in gastric antral vascular ectasia. The "watermelon stomach".

Gastric antral vascular ectasia was endoscopically diagnosed in seven patients. Pathologic characteristics of this entity were defined retrospectively, by studying endoscopic pinch biopsy slides from these seven patients and antrectomy specimens from five patients. A scoring system was developed, and the seven patients were compared prospectively with various control groups. Abnormalities of mucosal vessels (fibrin thrombi and/or ectasia) consistently distinguished patients from control antrectomies, normal biopsies, acute gastritis biopsies and atrophic gastritis biopsies (P=0.02, all comparisons). Spindle cell proliferation into mucosa also was characteristic of gastric antral vascular ectasia, distinguishing this disease from normals, acute gastritis, and atrophic gastritis (P≤0.039, each comparison). The presence of abnormal mucosal vessels (fibrin thrombi and/or ectasia) and spindle cell proliferation was similar in patient antrectomies compared to patient endoscopic biopsies. Therefore, we conclude that endoscopic biopsies can reliably diagnose gastric antral vascular ectasia, a vascular disorder characterized by abnormal mucosal vessels and spindle cell proliferation.

Carcinosarcoma of the colon. Report of a unique case with light and immunohistochemical studies

A unique case of carcinosarcoma of the colon is reported. The tumor invaded the bowel wall deeply, metastasized widely, resisted multi‐agent chemotherapy, and caused the patients death 4 years later. The tumor was composed of adenosquamous carcinoma admixed with sarcoma showing osseous, cartilaginous, and nonspecific spindle‐cell differentiation. Although carcinoembryonic antigen appeared limited to carcinoma cells, cytokeratin immunoreactivity was observed in both carcinoma and sarcoma cells. Like carcinosarcomas at other body sites, the finding of cytokeratin in sarcoma cells supports partial epithelial differentiation in this component, likely retained from carcinoma precursor cells. Cancer 58:1126‐1130, 1986.

Neoplastic pathology of oncogenic osteomalacia/rickets

Reported are two cases of oncogenic osteomalacia, each caused by a small mesenchymal tumor, with detailed assessment of the tumors by light microscopy, electron microsopy, and immunohistochemistry. One tumor was a primitive mesenchymal tumor with prominent giant cell and vascular components, and the second resembled the giant cell variant of soft parts chondroma. Osteoclast‐like, multinucleated giant cells and vascularity were prominent features in both tumors. Although the literature documents a histologically heterogeneous group of tumors as causing this syndrome, most have multinucleated giant cells and/or extensive vascularity. The high incidence of these two histologic features in this group of tumors suggests that either or both may be related to the pathogenesis and/or metabolic consequences of oncogenic osteomalacia/rickets.

Giant cell tumors of synovium (pigmented villonodular synovitis) involving the vertebral column

Giant cell tumors of synovium (pigmented villonodular synovitis) involving the vertebral column recently have been seen in two women: the third and fourth cases to be reported in the English‐language literature. Unlike the previously reported cases, both these tumors grew outside the dura and produced symptoms of spinal cord compression. The first case involved lumbar vertebrae 5 and 6; the second, lumbar vertebrae 2 and 3. Even though initial resection of both tumors was incomplete, the patients improved postoperatively. One tumor was known to be unresectable at the time of surgery. In the other patient, a recurrence of symptoms required second and third resections 4 and 8 months after the first, respectively. Although synovial giant cell tumors rarely metastasize, the rate of local recurrence is high, especially if excision is incomplete. For this reason, close follow‐up of patients with lesions in the spinal column is indicated. Increased physician awareness that synovial giant cell tumors can occur in the spine will help to ensure that these tumors are not misdiagnosed in this location.

Bizarre (pseudomalignant) granulation-tissue reactions following ionizing-radiation exposure a microscopic, immunohistochemical, and flow-cytometric study

Two patients developed extremely bizarre (pseudomalignant) granulation‐tissue reactions in the larynx and facial sinuses, following radiation therapy for carcinoma. Containing pleomorphic spindle cells and numerous (sometimes atypical) mitotic figures, both tumefactive lesions simulated high grade malignancies. While the pleomorphic cells contained vimentin immunoreactivity, they were nonreactive for low or high molecular weight keratin. Flowcytometric study of paraffin‐embedded tissues revealed DNA indexes of 0.75 and 1.0. Neither recurred locally nor spread distantly after therapy. Their granulation‐tissue growth pattern, and the presence of stromal and endothelial cells showing similar degrees of cytologic atypia were central to their recognition as benign. These findings show that severely atypical, sometimes aneuploid, granulation‐tissue reactions can occur following radiation exposure. Care should be taken not to misinterpret these lesions as malignant.

Granuloma annulare: A rare occipital lesion in infants and children

Subcutaneous granuloma annulare is a rare scalp lesion that occurs in infants and children. Occurrence in the occipital region, absence of bone involvement, slow growth, and foci of necrosis of collagen surrounded by palisading granulomatous inflammation are characteristic of this lesion. Although the cause remains unknown, it is not infectious and is more likely due to a defect in cell-mediated immunity. The prognosis after excision is excellent. Increased awareness that this peculiar granulomatous lesion can rarely occur in the soft tissue of the occipital region will help prevent confusion with neoplastic or infectious processes.

Three-dimensional studies of acellular glomerular basement membranes in dense-deposit disease

After digestion removed the cells from glomeruli of frozen kidney tissue, we employed scanning electron microscopy to examine the acellular glomerular basement membranes (AGBM) from normal kidneys and from kidneys of patients with dense-deposit disease (DDD). The AGBM showed previously unrecognized three-dimensional patterns of pathologic changes. When compared to normal controls, the AGBM in DDD appeared “rigid” and thickened. Other pathologic features included coarsely granular or undulating epimembranous surfaces punctuated by single or clustered crater-like deformities. Although epimembranous crater-like deformities have been observed in other glomerulopathies, the combination of “rigid” -appearing AGBM punctuated by crater-like deformities is thus far unique to DDD.