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Low-grade fibromyxoid sarcoma (LGFMS) is a rare sarcoma characterized by bland histologic features and a paradoxically aggressive clinical course. The hyalinizing spindle cell tumor with giant rosettes (HSCT) is a closely related tumor characterized by the presence of giant collagen rosettes. Only a single example of a metastasizing HSCT has been reported. A small subset of both LGFMS and HSCT display areas of increased cellularity and atypia which qualify as intermediate- to high-grade sarcoma; the significance of these features has not been definitively assessed. We present the clinicopathologic features of 77 cases of LGFMS and HSCT to determine the degree of overlap of these two lesions, their biologic behavior, and the significance of the occasional presence of intermediate- to high-grade sarcoma within both. The patients (33 female, 40 male) ranged from 3 to 78 years of age (median, 34 yrs). Fourteen cases occurred in patients less than 18 years of age. The tumors measured from 1 to 23 cm (median, 4.5 cm) and occurred predominantly in the trunk and lower extremities in both the deep (66 cases) and superficial (7 cases) soft tissues. In 15 cases, the tumor was present > 1 year before diagnosis. All tumors showed predominantly the typical hypocellularity and bland cytologic features of typical LGFMS; however, areas of hypercellularity and nuclear enlargement and hyperchromatism were identified in 12 of 73 (16%) and 7 of 73 (10%), respectively. Necrosis and mitotic activity >5/50 high-powered fields (HPF) were present in 6 of 73 (8%) and 5 of 73 (7%), respectively. Epithelioid areas were present in 33 of 73 (45%) and rosettes in 22 of 73 (30%). Follow up (54 cases; range, 2-192 mos; median, 24 mos; mean, 38 mos) showed 5 recurrences, 3 metastases, and 1 death. The diagnosis of LGFMS or HSCT was made prospectively in 51 patients; none had metastatic disease. Two of the metastatic tumors were LGFMS and one was a HSCT. LGFMS may occur more often in the pediatric population and show a much wider histologic spectrum than previously thought. A significant number of LGFMS possess inconspicuous collagen rosettes characteristic of HSCT, indicating that these two tumors are ends of a common spectrum rather than distinct entities. HSCT, like LGFMS, are low-grade sarcomas with metastatic potential. The presence of focal areas of intermediate- to high-grade sarcoma does not portend a worse outcome in the short term. The better prognosis reflected in this study compared with previous ones might reflect the fact that all were initially diagnosed as sarcomas and treated with aggressive surgery. The fact that the only three patients to develop metastatic disease were patients whose LGFMS or HSCT was identified retrospectively supports this concept.

We report the findings of 19 cases of a previously undescribed spindle cell tumor of soft tissues that resembles a low-grade fibromyxoid sarcoma but contains distinctive rosettelike structures. The tumors occurred principally as a painless, slowly growing, deeply situated mass of the proximal extremities in young to middle-aged adults (age range 14-65 years; mean 38). Although grossly circumscribed, the tumors had infiltrative borders microscopically and were composed of bland spindled cells situated in a hyalinized to myxoid stroma. The most characteristic feature of the tumor was scattered large rosettelike structures that often merged with serpinginous areas of dense hyalinization. The rosettes consisted of a central collagen core surrounded by a rim of rounded cells morphologically and immunophenotypically different from the cells of the spindled stroma. These cells expressed a number of antigens, including S-100 protein, neuron-specific enolase, and leu 22, in contrast to the stroma, which usually lacked these antigens. Of the 12 patients with available follow-up information, one patient treated with simple excision clinically developed local recurrence of the tumor 20 months after initial biopsy. No other recurrences were reported during the limited follow-up period, and no patient developed metastatic disease. However, the favorable prognosis of the patients in our series to date may relate to the limited follow-up period (approximately 3 years), as well as initial treatment by wide excision in nearly half of the patients. We regard the hyalinizing spindle cell tumor with giant rosettes as a distinctive type of low-grade fibroblastic tumor that with time may prove to behave similar to a low-grade fibromyxoid sarcoma and, hence, to represent an unusual variant thereof.

Laparoscopic surgery frequently requires tattooing of endoscopically identified sites for localization during surgery. Some tattooing agents cause serious tissue injury, which must be recognized in pathologic examination. Seven surgically resected colons were reviewed after injection with methylene blue or India ink at intervals of 1 day to 7 weeks before surgery. Early reactions to India ink included necrosis, edema, and neutrophilic infiltration in the submucosa and muscularis propria. Vessels were inflamed but without fibrinoid necrosis. Early reactions to methylene blue included ischemic ulceration, necrosis, and eosinophilic infiltration in the submucosa as well as fibrinoid necrosis of vessel walls. In the repair of methylene-blue injury, obliterative intimal fibrosis was seen in vessels. Such changes were absent in the colons injected with India ink. The India ink remained remained visible with the naked eye and microscopically 7 weeks after injection. Methylene blue was not grossly visible 7 days after injection, and only microscopic particles of pigment remained in widely scattered macrophages. In light of these findings, the amount of ink injected should be minimized and the injection site should be completely resected at surgery. Methylene blue is a poor tattoo agent, but its occasional use continues, and pathologists should recognize the resulting reaction.

To investigate possible associations of nodular regenerative hyperplasia (NRH) with antitumor chemotherapy, we reviewed 72 partial hepatic resections (55 with metastatic tumor, 12 hepatocellular carcinomas, and five benign neoplasms). Thirty autopsy livers from adults without malignancies served as controls. Studies included hematoxylin and eosin, reticulin, and trichrome stains and immunostaining for proliferating cell nuclear antigen (PCNA). Five of 72 livers (7%) had NRH. All five patients had received chemotherapy, one by intrahepatic artery infusion. Four had received chemotherapy 2 months or less before undergoing partial hepatectomy. These five cases represented 15% of the 33 patients who received chemotherapy. No NRH was seen in autopsy control livers. In contrast to NRH, multiple hyperplastic foci were seen in 28 of 72 livers (39%). This finding did not correlate with chemotherapy. Two of 30 control livers (7%) showed similar mild regenerative changes. In only one case of NRH was PCNA staining increased over controls. A band of PCNA-positive hepatocytes was seen adjacent to the tumor in 21 cases, suggesting that the presence of tumor may cause a local increase in PCNA expression. Mitoses in hepatocytes and assessment of the thickness of liver cell plates were more sensitive indicators of regeneration than PCNA. Vascular changes, such as sinusoidal fibrosis (11 of 72 cases), thickened hepatic arterioles (13 of 72 cases), and mild thickening of central veins (10 of 72 cases), did not correlate with NRH, hyperplastic foci, or chemotherapy. No cases of hepatoportal sclerosis were identified.