Soft tissue gliomatosis. Morphologic unity and histogenetic diversity.

Normal-appearing tissues in non-native sites constitute one of the more common morphologic expressions of abnormal development. The presence of pancreas in the wall or on the serosa of the small intestine and adrenal cortical tissue in a hernia sac are two familiar examples of heterotopias. We report our experience of mature glial tissues in the soft tissues of six children who were between the ages of 4.5 months and 2 years when they presented with a solitary mass on the chest wall (three cases), scalp (two cases) and gluteal region (one case). These tumors were all characterized by pale-staining fibrillary foci of mature neuroglia, which were intensely immunoreactive for glial fibrillary acidic protein in each case. One of the two scalp lesions was accompanied by a nodule of cartilage and a meshwork of pseudovascular spaces, which were decorated with antibodies to vimentin and epithelial membrane antigen consistent with meningothelial tissue. The histogenesis of the neuroglial tissue in the gluteal region and scalp was, respectively, on the basis of a recurrence of a sacrococcygeal teratoma in the former case and sequestered encephaloceles in the last two cases. A facile explanation for the occurrence of neuroglial tissue in the soft tissue of the chest wall in the remaining three cases was less than obvious as none of the patients had accompanying neurologic or anatomic defects and all were in a nonmidline location. These three cases of soft tissue gliomatosis of the chest wall are similar to an earlier example in the recent literature whose histogenesis was as enigmatic as it proved to be in our three cases. Although the histologic and immunohistochemical features of these six cases were very similar in each instance, their origin varied from a recurrent sacrococcygeal teratoma and sequestered encephaloceles to essentially unknown.

Biphasic and monophasic sarcomatoid carcinomas of the lung. A reappraisal of 'carcinosarcomas' and 'spindle-cell carcinomas'.

To address the premise that pulmonary "carcinosarcomas" and spindle-cell carcinomas are part of a single clinicopathologic continuum, the authors studied 21 examples of such lesions as defined by World Health Organization criteria. Two biphasic tumors demonstrated an admixture of overt carcinoma with other foci showing partial rhabdomyogenic differentiation; 15 others were histologically similar but lacked "heterologous" sarcoma-like elements; and four lesions were monophasic spindle-cell sarcomatoid carcinomas. One of the latter also contained rhabdomyosarcoma-like areas by light microscopy. Sarcomatoid components were reactive for keratin and/or epithelial membrane antigen (EMA) in 18/21 cases. In addition, desmin and muscle-specific actin were co-detected in the same spindle cells that were keratin-positive in 4 tumors, 3 of which were those with partially myogenic histologic features. Vimentin was present in keratin- or EMA-reactive sarcomatoid cells in 12 neoplasms, and all cases were labeled with an antibody to collagen type IV. Survival was poor in this group of patients; only 1 was alive at last contact. These data support the contention that "carcinosarcoma" of the lung is part of a spectrum with "spindle-cell carcinoma." It is proposed that the terms "biphasic sarcomatoid carcinoma" and "monophasic sarcomatoid carcinoma" are more apt descriptors for such tumors.

Mutated c-K-ras in small pancreatic adenocarcinomas.

The objective of this study was to determine whether small human pancreatic adenocarcinomas contain activated c-K-ras as an approach to answering the question of whether c-K-ras mutation is an early change in this disease. Eight pancreatic adenocarcinomas in the range 1.2-3 cm were analyzed for c-K-ras mutation at codon 12 by amplifying the c-K-ras gene around codon 12 out of paraffin-embedded tissue sections using the polymerase chain reaction. c-K-ras mutations were detected by allele-specific oligonucleotide hybridization. Six of the eight small pancreatic adenocarcinomas contained mutated c-K-ras at codon 12, position 2, and two of the six tumors had an additional mutation at position 1 of codon 12. Our results indicate that small pancreatic adenocarcinomas are similar to large, late-stage pancreatic adenocarcinomas in that 75% of the tumors analyzed contain mutated c-K-ras at codon 12, position 2. These data suggest that c-K-ras mutation occurs early and may therefore have a role in initiation of human pancreatic adenocarcinoma.

Geniculate ganglion: anatomic study with surgical implications.

The geniculate ganglion and adjacent segments of the facial nerve were dissected in 11 human temporal bones to study the extent and distribution of ganglion cells. A histologic basis for the use of geniculate ganglionectomy as the treatment for geniculate neuralgia was sought. In 9 of 11 specimens (81.8%), the ganglion cell bodies appeared to be aggregated at the apex of the genu close to the origin of the greater superficial petrosal nerve. The mean ratio of the width of the ganglion cell cluster to the width of the facial nerve trunk at the level of the genu was 0.4. In two specimens, significant anatomic variation was present. One specimen showed extension of cell bodies into the labyrinthine segment of the facial nerve; another specimen showed a single ganglion cell in the region of the genu. These findings lead us to postulate that geniculate ganglionectomy may be ineffective as the sole treatment for certain cases of geniculate neuralgia, and that nervus intermedius section may also be required to achieve a more complete deafferentation.

Characterization of the ELSV transgenic mouse model of pancreatic carcinoma. Histologic type of large and small tumors.

Carcinomas of the pancreas that developed in Tg(Ela-1, SV40E)Bri18 and Tg(Ela-1, SV40E+Ela-1, neo)Bri19 strains of transgenic mice were classified into eight histologic patterns. Most were variants of acinar cell carcinoma, but cystic and undifferentiated carcinomas were found. The spectrum of phenotypes was similar in small and large carcinomas, but the small group included a higher fraction of well-differentiated tumors and fewer poorly differentiated and anaplastic tumors. The incidence of islet cell tumors was far higher in the Bri18 strain (77%) than in the Bri19 strain (1.6%). Islet cell hyperplasia was much more prevalent in Bri18 than Bri19 mice. In both strains, the nontumorous pancreas showed acinar cell dysplasia with a more abnormal and distinctive pattern in the Bri19 strain. While the spectrum of exocrine tumor phenotypes is similar, significant differences occurred between these two transgenic mouse strains as models for pancreatic carcinogenesis.