Soft tissue sarcoma and military service in Vietnam: a case-control study.

A case-control study was conducted in men who were of draftable age during the Vietnam conflict to examine the association of soft tissue sarcomas (STSs) with military service in Vietnam as well as other host and environmental risk factors. A total of 217 STS cases selected from the Armed Forces Institute of Pathology were compared to 599 controls for Vietnam service, occupational and nonoccupational exposure to various chemicals, occupational history, medical history, and life-style (smoking, alcohol, coffee, etc.). Military service information was verified by a review of the patient's military personnel records. Other information was ascertained from a telephone interview with either subjects or their next of kin. Cases and controls were stratified on the basis of the hospital type (civilian, Veterans Administration, and military); the Mantel-Haenszel estimate of the odds ratio (OR), adjusted for the effects of the stratification variable, was calculated. Vietnam veterans in general did not have an increased risk of STS when compared to those men who had never been in Vietnam (OR, 0.85; 95% confidence interval, 0.54-1.36). Subgroups of Vietnam veterans who had higher estimated opportunities for Agent Orange exposure seemed to be at greater risk of STSs when their counterparts in Vietnam were taken as a reference group. However, this risk was not statistically significant.

Chondroid lipoma. A unique tumor simulating liposarcoma and myxoid chondrosarcoma.

We report 20 cases of a peculiar fatty tumor that occurred in 16 female and four male patients who were 14-70 years old (median, 36 years). Most lesions were situated in the subcutis, superficial muscular fascia, or skeletal muscle of the limbs and limb girdles (15), trunk (3), and the head and neck (2). They were 1.5-11 cm in size (median, 4 cm) and usually described as yellow (13 of 15) and encapsulated (13 of 15). Microscopically they were well circumscribed and consisted of nests, strands, and sheets of eosinophilic and vacuolated cells, which contained glycogen and fat droplets, resembling brown fat cells, lipoblasts and chondroblasts. In all cases there was a variable background of mature adipose tissue associated with a prominent, partially fibrinous to hyalinized myxoid matrix that contained acid mucopolysaccharides usually resistant to hyaluronidase digestion. Several cases had foci of serous atrophy, perivascular fibrosis, and small thrombi; two were focally calcified. The lesions stained for S100 protein (11 of 12), vimentin (10 of 11), and CD68 antigen with KP1 (9 of 11); focal staining for keratin was also seen (4 of 11), but none stained for epithelial membrane antigen or actin or with HMB45. Follow-up in 12 cases (median, 9.5 years) revealed no local recurrences or metastases. Despite its deep location and atypical cellular features, the lesion's nonaggressive behavior suggests it is benign and neither a myxoid liposarcoma nor a myxoid chondrosarcoma, with which it is most frequently confused. The presence of glycogen in vacuolated fat cells is similar to brown fat, and the presence of sulfated stromal mucins supports focal chondroid differentiation. Although the pathogenesis remains uncertain, a lipoma with hibernomatous features, myxoid change, chondroid metaplasia, and secondary degenerative features is favored over a lipogranulomatous process.

Myolipoma of soft tissue.

Nine cases of a previously undescribed benign soft tissue tumor are reported. They were composed of variable amounts of benign smooth muscle and mature adipose tissue. Patient ages ranged from 28 to 73 years. One was located in the subcutaneous adipose tissue, one in the rectus sheath of the anterior abdominal wall, two within the abdominal cavity and attached to the abdominal wall, two in the inguinal region, and three in the retroperitoneum. Sizes varied between 3.5 and 26 cm and averaged 16 cm in greatest dimension. Two of the retroperitoneal tumors were incidental findings during other operative procedures. The remaining seven cases were clinically palpable masses. Eight of the nine lesions were originally diagnosed as benign, and another (retroperitoneal) was diagnosed as well-differentiated liposarcoma. Five of the tumors were at least partially encapsulated. In three of the cases, a nonlipomatous component was grossly recognized. Although the benign nature of this lesion is usually recognized in superficial locations, deeply situated tumors are more likely to be confused with a well-differentiated liposarcoma.

Spindle cell hemangioendothelioma. A low-grade angiosarcoma resembling a cavernous hemangioma and Kaposi's sarcoma.

Twenty-six cases of a newly recognized form of vascular tumor are presented. The tumor may occur at any age, has a male predominance, and develops preferentially in the dermis and subcutaneous tissues of the distal extremities. Histologically it combines the features of both a cavernous hemangioma and Kaposi's sarcoma. It is composed of thin-walled cavernous vessels which may be dilated, partially collapsed, or filled with organizing thrombi and phleboliths. These areas are intimately associated with spindled areas reminiscent of Kaposi's sarcoma. The spindled areas differ from Kaposi's sarcoma by the presence of occasional epithelioid endothelial cells, which sometimes display vacuolization. Follow-up information in 14 cases indicates that nine patients experienced "recurrences." One patient, who also received radiotherapy, developed regional lymph node metastasis 40 years after diagnosis and following 19 recurrences. No patient, however, has died of his disease, despite relatively limited surgical excision. The term "spindle cell hemangioendothelioma" is suggested for this vascular tumor of low-grade malignancy.

Inflammatory fibrosarcoma of the mesentery and retroperitoneum. A tumor closely simulating inflammatory pseudotumor.

We report 38 cases of inflammatory fibrosarcoma occurring in 23 females and 15 males, 2 months to 74 years of age (median, 8.5 years; mean, 15 years) with symptoms of abdominal pain (17 cases), anemia (21 cases), fever (14 cases), mass (16 cases), and gastrointestinal obstruction (7 cases). Primary tumor sites included mesentery and retroperitoneum (31 cases), omentum (two cases), mediastinum (two cases), liver (one case), diaphragm (one case), and abdominal wall (one case). Sizes ranged from 2.4 cm to 20 cm (mean, 9.6 cm). Follow-up data in 27 cases revealed local recurrences in 10 patients, with multiple local recurrences in three and histologically proven distant metastases to lung (two cases) and brain (one case). Five patients died from their disease (median, 20 months). All tumors, including metastases, consisted of fibroblasts, myofibroblasts, and plasma cells, with variable degrees of fibrosis and calcification. Immunostains indicate myofibroblastic differentiation; 18 of 20 (90%) stained for actin, 15 of 18 (83%) for vimentin, and 10 of 13 (77%) for keratin (primarily in a submesothelial location). Ultrastructural studies also disclosed myofibroblastic features. The locally aggressive, recurrent nature of these neoplasms, as well as the occurrence of metastases and tumor deaths, indicate that they are potentially malignant neoplasms that we believe are better classified as inflammatory fibrosarcomas, not as cellular inflammatory pseudotumors.

Epithelioid sarcoma. Diagnosis, prognostic indicators, and treatment.

A retrospective review of 241 cases of epithelioid sarcoma reaffirmed the propensity of this tumor to occur in the distal extremities of young adults. The tumor was generally firm and nontender, and involved the dermis, subcutis or deeper soft tissues, particularly fascial planes, aponeuroses, and tendon sheaths. Follow-up data, available in 202 cases (84%), showed a 77% recurrence and a 45% metastatic rate. The most common initial sites of metastasis were lymph nodes (48%) and lungs (25%). A more aggressive course was associated with a proximal or axial tumor location, increased size and depth, hemorrhage, mitotic figures, necrosis, or the presence of vascular invasion. More favorable behavior was observed when the tumor arose in younger individuals, in distal extremities, or in females between the ages of 10 and 49. (The last observation calls for further work with steroid receptors.) Radical excision or amputation still appears to be the initial treatment of choice, though adjunctive high-dose radiotherapy to the excision site may prove to be of additional value.

Fibrolipomatous hamartoma of nerve. A clinicopathologic analysis of 26 cases.

Nineteen cases of fibrolipomatous hamartoma of nerve without macrodactyly and seven cases with macrodactyly are discussed. Twenty-five involved the hand, wrist, palm, and finger, and one case involved the foot. Nineteen patients had isolated fibrofatty enlargement of nerve, while seven had macrodactyly in addition to the peripheral nerve changes. Involved nerves included the median nerve, ulnar nerve, an unidentified nerve near the elbow, and a nerve on the dorsum of the foot. Four of nine patients with neurologic symptoms of pain or paresthesias had physical findings compatible with compression neuropathy, and two others were described as having carpal tunnel syndrome. Most patients had been aware of a mass for several years. Microscopically, the lesion was characterized by fibrofatty enlargement of nerve with massive epineural and perineural fibrosis. In two of the cases with macrodactyly, the fibrofatty enlargement of the nerve was associated with overgrowth of bone and the surrounding subcutaneous tissues. In one case, the perineural fibrosis was associated with metaplastic bone. The histogenesis of fibrofatty overgrowth of nerve has been disputed. Mature fat cells have been described within the normal nerve sheath, and it is thought that proliferation of these cells leads to the fatty enlargement of the nerve and its coverings. The relationship of these neural changes to the development of macrodactyly remains controversial. Follow-up in 18 patients (69%) reveals a benign course following biopsy, limited excision, or division of the flexor retinaculum in the wrist.

Intravascular fasciitis: a report of 17 cases.

Seventeen cases of intravascular fasciitis were reported from the files of the AFIP (14 cases) and the Pathology Department, Thomas Jefferson University Hospital (three cases). It is characterized by the histologic features of nodular fasciitis but with intraluminal, intramural, and extramural involvement of small to medium-sized veins and arteries and multinodular or serpentine growth along the course of affected blood vessels. A painless, slowly growing mass was most common. Fourteen patients (82%) were under age 30 (range 1/2-57 years); the sex ratio was about equal. Seven cases were located in the upper extremity (three hand, two wrist or forearm, two shoulder), three on the ankle or lower leg, five on the head and neck, and two in the chest wall and breast. Most cases were small with a mean diameter of 1.5 cm, but two were elongated masses measuring 4-5 cm in length. At surgery, four cases showed intimate association with large veins or arteries. This type of fasciitis is rare and has been found in only one of 14 consecutive cases of modular fasciitis operated at this university hospital between 1969 and 1978. Six of 15 consultation cases were originally confused with sarcoma. Intravascular fasciitis is benign. Seven patients were free of disease from 2.5 to 20 years (mean 9.5 years); two patients had local recurrences.

Malignant melanoma of soft parts. A reassessment of clear cell sarcoma.

A retrospective study of 141 cases of clear cell sarcoma of tendons and aponeuroses revealed that the tumor occurred predominantly in young patients between 15 and 35 years of age, was slightly more common in female than in male patients, and originated chiefly from tendons, aponeuroses, and fascial structures of the extremities with a predilection for the feet and knees. The tumor presented as an insidiously growing mass causing pain or tenderness in slightly more than half of the patients. The preoperative duration of symptoms varied greatly, and in 29 cases the time interval between discovery of the tumor and operation exceeded 5 years. Microscopically, the tumors varied little in appearance and were composed of short fascicles of fusiform cells with a clear to granular eosinophilic cytoplasm, vesicular nuclei with prominent nucleoli, and occasional multinucleated giant cells. Melanin was demonstrated in 72% of the 92 tumors in which the Fontana or Warthin-Starry preparation for melanin was performed. S-100 protein, a neuroectodermal marker, was positive in 13 of 19 cases. Follow-up information was available in 115 patients. Thirty-four (29.6%) were alive and well with no evidence of recurrence. Twenty-four (20.9%) patients were alive with one or two recurrences, three (2.6%) were alive following pulmonary lobectomy for metastatic sarcoma, and one was alive with metastasis in the thoracic spine. Fifty-three of the 115 patients with follow-up information had died, 50 from metastatic tumor and three from miscellaneous causes. The prevailing sites of metastasis were the lung and the regional lymph nodes. The exact histogenesis remains obscure, but the presence of intracellular melanin in two-thirds of the cases supports origin from migrated neural crest cells with the capacity for producing melanin. For this reason the term, malignant melanoma of soft parts, seems preferable over the purely descriptive term of clear cell sarcoma.

Plexiform fibrohistiocytic tumor presenting in children and young adults. An analysis of 65 cases.

We report 65 cases of a hitherto undescribed neoplasm that occurs chiefly in children and young adults, and has morphologic features reminiscent of both a fibrous histiocytoma and fibromatosis. The median age of the 65 patients was 14.5 years; two-thirds (67.7%) of the patients were younger than 20 years. The lesion was more common in female patients (46 cases) than in male patients (19 cases). It usually presented as a slow-growing, poorly demarcated dermal or subcutaneous mass that rarely exceeded 3 cm in greatest diameter. Its most common location was the upper extremity (63.1%), especially the regions of shoulder and forearm. Under the microscope, the lesions were characterized by a multinodular or plexiform proliferation of histiocyte- and fibroblast-like cells associated with multinuclear giant cells. Differential diagnosis chiefly includes cutaneous fibrous histiocytoma, plexiform neurofibroma, fibromatosis, and benign and malignant giant cell tumor. Twenty of the 32 cases (62.5%) with follow-up information were alive and well after local excision, but the tumor recurred in 12 cases (37.5%). In two patients with recurrence, the disease metastasized to regional lymph nodes 9 and 36 months after the initial excision, respectively. Metastasis to the lung or other organs was not observed. We were unable to demonstrate a close correlation between biologic behavior and any specific clinical or morphologic parameter.

Proliferative fasciitis and myositis of childhood.

Eleven cases of proliferative fasciitis and myositis in children, ages 2.5 months to 13 years, are presented. Eight lesions averaging 2.3 cm in size occurred in the extremities, two in the head and neck region and one on the chest wall. Like proliferative fasciitis and myositis in adults, these lesions consisted of admixtures of large polygonal to spindled, ganglion-cell-like fibroblasts with vesicular nuclei and prominent inclusion-like nucleoli. Seven of 11 lesions were initially diagnosed as sarcomas, most commonly rhabdomyosarcoma. Four patients were treated by wide excision (three with regional lymphadenectomy), three received chemotherapy, and one was given radiation therapy. There were some histologic differences from adult-type proliferative fasciitis and myositis. The childhood lesions were generally well circumscribed, lobulated, extremely cellular with less collagen production, and often associated with acute inflammation and microscopic foci of necrosis. Immunohistochemical comparison with adult proliferative fasciitis and myositis showed similar immuneprofiles; the ganglion-like cells stained for vimentin and actin and focally with KP1, suggesting myofibroblastic and histiocytic features. None of the lesions stained for keratin, desmin, or S-100 protein. Ultrastructural examination of two cases revealed cells with a constellation of fibroblastic, myofibroblastic, and histiocytic features. Follow-up of seven patients, averaging 58 months from diagnosis, confirmed that all are alive and well. Recognition of this cellular variant of proliferative fasciitis and myositis is important to prevent misdiagnosis as a sarcoma and unnecessary, excessive therapy.

Plexiform malignant peripheral nerve sheath tumor of infancy and childhood.

We present nine cases of an atypical cellular peripheral nerve sheath tumor, designated plexiform malignant peripheral nerve sheath tumor (MPNST) of infancy and childhood, occurring in five boys and four girls aged 50 days to 13 years (median, 1.5 years). The tumors were located in the lower extremities (five cases), upper extremities (three cases), and the orbital region (one case), and they ranged from 1.5 to 8 cm in size (median, 3 cm). Two lesions were congenital, and another was associated with a history of von Recklinghausen's disease. Follow-up, available in six cases, ranged from 6 months to 15 years (median, 51 months); four patients had local recurrences within 8 to 31 months after excision of the initial lesion, and one with an orbital tumor died of locally invasive disease within 6 months. Histologically, the initial lesions were characterized by a predominantly superficial location within the dermis and subcutis, with occasional extension into deeper soft tissues, had infiltrative or sharply demarcated margins, and resembled entangled or intertwined hypercellular nerve trunks, resulting in a plexiform appearance at low magnification. The nuclei were oval to serpentine with a vesicular chromatin pattern and small basophilic nucleoli; mitoses were seen in all cases and averaged from 1 to 18/10 high-power fields (hpf) (median, 4/10 hpf). Neither necrosis nor vascular invasion was seen. Features diagnostic of plexiform or cellular schwannoma, such as nuclear pleomorphism, Antoni B areas, thick-walled hyalinized blood vessels, and secondary degenerative features were lacking. Other than a prominent plexiform architecture, the lesions were indistinguishable from MPNST occurring in other sites in infants and children. Although none metastasized, the histologic similarity of plexiform MPNST to other childhood MPNST, its relatively high propensity for local recurrences, and its potential to behave in a locally aggressive manner indicate that it is best regarded as low-grade malignant. Overall, the behavior of plexiform MPNST is better than other MPNST in children, probably because of its relatively small size, peripheral and superficial location in most instances, absence of necrosis or vascular invasion, occurrence in young patients, and infrequent association with von Recklinghausen's disease rather than a function of its prominent plexiform architecture. Distinction of plexiform MPNST from cellular and plexiform schwannoma, plexiform neurofibroma, and hamartomatous lesions of childhood is important. Complete excision should be ensured to prevent local recurrences and potential metastases.

Sclerosing epithelioid fibrosarcoma. A variant of fibrosarcoma simulating carcinoma.

We report 25 cases of a peculiar sclerosing epithelioid variant of fibrosarcoma (SEF) simulating an infiltrating carcinoma. The tumors occurred primarily in the deep musculature and were frequently associated with the adjacent fascia or periosteum. The patients' ages were 14 to 87 years (median, 45). Fourteen were male and 11 female. The tumors were located in the lower extremities and limb girdles (12 cases), trunk (9), upper limb girdles (2), and neck (2). They measured 2 to 14.5 cm in greatest dimension (median size, 7 cm) and were gray to white and firm. Histologically, the lesions were characterized by a proliferation of rather uniform, small, slightly angulated, round to ovoid epithelioid cells with sparse, often clear cytoplasm arranged in distinct nests and cords. In all cases there was prominent hyaline sclerosis, sometimes reminiscent of osteoid or cartilage and foci of conventional fibrosarcoma. Occasional myxoid zones with cyst formation and foci of hyaline cartilage, calcification, and metaplastic bone were also seen. Mitotic figures were generally scarce. Vimentin was detected in 13 of 14 cases, epithelial membrane antigen in seven, S100 protein in four, and neuron-specific enolase in two. Cytokeratins were detected with AE1/AE3 and CAM 5.2 in two cases. Leukocyte common antigen, CD68 antigen, HMB45, desmin, and alpha-smooth muscle actin were negative in all cases. In 13 of 14 cases, 75% or more of the cells stained for proliferating cell nuclear antigen (PCNA). Ki67 immunostaining with MIB 1 showed low proliferative activity in all cases, averaging 5% of tumor cells or less. In all cases, p53 was detected by immunohistochemical methods; bcl-2, an antiapoptosis marker, was detected in more than 90% of the cells in 11 of 12 cases. Ultrastructurally, both the epithelioid and spindled tumor cells had features of fibroblasts. Follow-up in 16 cases ranging from 13 months to 17 years 3 months (median, 11 years 4 months) revealed persistent disease or local recurrences in 53% of patients and metastases in 43%. The metastases were to the lungs (4 cases), skeleton (3), chest wall/pleura (3), pericardium (1), and brain (1). Four patients died of disease, four were alive with disease, two were known to be alive but disease status unknown, and six had no evidence of further disease at last follow-up. The data suggest that SEF is a relatively low-grade fibrosarcoma; yet it is fully malignant despite the presence of histologically benign-appearing foci. The proliferation markers PCNA and Ki67 did not correlate with prognosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Malignant lymphoma. A study of 75 cases presenting in soft tissue.

We report 75 cases of malignant lymphoma presenting in soft tissue taken from the files of the Armed Forces Institute of Pathology. All histologic subtypes with the exception of lymphoblastic lymphoma were represented. Our findings indicate that virtually any soft tissue site may be involved; there is no sex predilection; and size is not helpful in predicting survival. Among the 55 patients for which race was known, there were no black patients. Thirty-three patients with extensive evaluations at the time of diagnosis had no evidence of disseminated disease, but eight of these exhibited widespread disease within 3 months of diagnosis, and seven of the eight died of disease (median survival, 4 months). The remaining 25 patients had much better outcomes; 18 of 19 with intermediate and high-grade lymphomas were alive and well at a median of 74 months after diagnosis. Some tumors exhibited a propensity for involvement of remote soft tissue sites.

Malignant fibrous histiocytoma associated with hyperlipoproteinemia.

A unique case of malignant fibrous histiocytoma arising within the thigh of a patient with Type II A (hypercholesterolemic) hyperlipoproteinemia is described. The tumor, which appeared grossly as a benign tuberous xanthoma, demonstrated pleomorphic spindled and multinucleated cells focally in the distinct storiform pattern of a malignant fibrous histiocytoma and areas composed of bland xanthoma cells associated with cholesterol deposits. Foci of xanthoma cells with mildly atypical nuclei admixed with highly pleomorphic cells were also noted. These unusual histologic features--as well as the uniform staining of all the tumor cells with anti-alpha-1-antichymotrypsin and the absence of anti-alpha-1-antitrypsin and of anti-lysozyme staining--support the conclusion that all elements of this malignant tumor were derived from a common mesenchymal precursor. The exaggerated histiocytic capability of the tumor cells in the form of xanthomatous change was probably in response to the hyperlipoproteinemic microenvironment.

Ossifying fibromyxoid tumor of soft parts. A clinicopathological analysis of 59 cases.

We describe 59 cases of a microscopically unique neoplasm that has not been previously reported. The tumor almost exclusively affected adults (range 14-79 years) and had a male predominance (38 men and 21 women). It presented in most cases as a small, painless, well-circumscribed mass (median, 4 cm) in subcutis or muscle. It occurred chiefly in the upper and lower extremities (40 cases) and less frequently in the trunk (11 cases) and the head and neck region (eight cases). Microscopically, the tumor was partly lobulated and composed of small, round cells that had vesicular nuclei and indistinct cytoplasm. Typically, the cells were arranged in a cord- or nestlike pattern within a myxoid matrix that frequently showed transitions toward hyaline fibrosis and focal osteoid formation. In about two-thirds of the cases, the cells contained immunoreactive S-100 protein. An additional typical feature, seen in 48 (81%) of the 59 cases, was the presence of an incomplete shell of mature bone in the capsular region of the tumor. Follow-up information, available in 41 cases, revealed that 11 patients (27%) experienced one or more recurrences. One patient with three recurrences developed a second tumor in the opposite thigh, presumably a metastasis. None of the patients died of the tumor, but three died of causes unrelated to the disease. Although the histogenesis is uncertain, cartilaginous or neural origin seem to be most likely. Until this issue is resolved, we prefer the descriptive and less committal designation of "ossifying fibromyxoid tumor of soft parts."

Crystal-storing histiocytosis associated with lymphoplasmacytic neoplasms. Report of three cases mimicking adult rhabdomyoma.

Massive crystal deposition is rare in lymphoplasmacytic (LPc) or plasma cell neoplasms. We report three cases in which the accumulation of crystals in histiocytes closely reproduced the histologic features of adult rhabdomyoma. The patients, all female, aged 18, 77, and 78 years, presented with tumor of cervical lymph nodes (two cases) or the otolaryngic mucosa (two cases). In addition, two patients had monoclonal serum or urine immunoglobulin (IgM-kappa-1, unknown-1), and one had renal and bone marrow involvement on biopsy. This last patient died of acute renal failure at 5 months, another was alive without disease at 8 years, and the remaining one was lost to follow-up. Lymph nodes, mucosae, and kidney showed a neoplastic LPc infiltrate masked by sheets of large benign histiocytes containing sheaves of crystals. Paraffin-section immunohistochemistry demonstrated monoclonal staining of the LPc cells in all cases (IgM-kappa-2, IgA-kappa-1) and of the crystals (IgM-kappa) in one case. In all patients, the crystal-containing cells were positive for KP-1 (CD68), but not for desmin, muscle-specific actin, or myoglobin. These findings suggest that, in any case of adult rhabdomyoma in which the histologic findings are not typical, a crystal-storing histiocytosis should be ruled out: recognition of the atypical LPc component and the histiocytic immunophenotype of the crystal-storing cells will help prevent a serious misdiagnosis.

Fibromatosis of the breast. A clinical and pathological study of 28 cases.

The clinical and pathologic findings of 28 examples of fibromatosis of the breast not involving the deep fascia or chest wall are reported. Five of the 20 lesions treated by local excision recurred. Recurrences developed within a 4 to 8 month period following surgery in four of the five instances, and 6 years after surgery in one instance. One lesion recurred five times over a period of 3 years. None of the patients died from their disease, and none developed a metastasis. Those lesions that recurred had been inadequately excised initially, since surgical margins showed fibromatosis. Specific histological features, such as size, cellularity, atypia, and mitotic figures, were not helpful in predicting recurrence. Although local excision appears to have been adequate in the majority (75%) of the patients, the infiltrative nature of fibromatosis necessitates documentation of tissue margins in order to avoid the possibility of recurrence. The differential diagnosis includes benign reactive processes (such as keloid and nodular fasciitis), fibrous histiocytoma, low-grade spindle-cell (metaplastic) carcinoma, and fibrosarcoma.

Malignant peripheral nerve sheath tumors (malignant schwannomas) in children.

We studied the clinical and pathologic features of 78 malignant peripheral nerve sheath tumors in children less than or equal to 15 years of age. There were 42 boys and 36 girls, with a median age of 10 years. The majority of the tumors (42, or 54%) were central or axial in location; the rest were peripheral. Sixteen patients (21%) had a history of von Recklinghausen's disease. Fourteen (18%) had a malignant peripheral nerve sheath tumor arising in a nerve trunk or a neurofibroma and were unassociated with von Recklinghausen's disease. Patients typically presented with a painful mass of variable duration. Tumors ranged from 2 to 33 cm (median, 7.5 cm) and demonstrated a wide histologic spectrum that included spindled, epithelioid, and primitive neuroepithelial-like cells as well as heterologous elements (11). Immunohistochemical staining revealed S-100 protein in 28 of 50 cases (56%) as well as vimentin (13 of 21 cases, or 62%), Leu 7 (22 of 49 cases, or 45%), actin (eight of 20 cases, or 40%), and keratin (seven of 27 cases, or 26%). Survival status was known for 57 patients (73%). Kaplan-Meier estimates revealed a median survival of 45 months. Half of the patients had local recurrences at 12 months, and half had metastases at 24 months, most commonly to lungs, followed by lymph nodes, liver, bone, soft tissue, and brain. Age greater than or equal to 7 years, male sex, presence of von Recklinghausen's disease, central location, larger tumor size, and tumors with greater than or equal to 25% necrosis were found to be potentially significant adverse prognostic indicators by univariate analysis. Multivariate analysis revealed that larger tumor size, age greater than or equal to 7 years, tumor necrosis greater than or equal to 25%, and von Recklinghausen's disease to be independent adverse prognostic factors.

Atypical decubital fibroplasia. A distinctive fibroblastic pseudotumor occurring in debilitated patients.

We report 28 cases of atypical decubital fibroplasia, a distinctive pseudosarcomatous fibroblastic proliferation occurring primarily but not exclusively in physically debilitated or immobilized patients. The subjects included 16 women and 12 men ranging in age from 15 to 95 years. Peak incidence was in the 8th and 9th decades of life. Anatomic locations included the soft tissues overlying the shoulder (eight cases), posterior chest wall (five cases), sacrum (five cases), greater trochanter (four cases), buttock (two cases), thigh (two cases), and arm (two cases). Symptoms were due to a painless mass of 3 weeks' to 6 months' duration. Most lesions were ill-defined, focally myxoid masses that ranged from 1 to 8 cm. Histologically, they were situated in the deep subcutis and secondarily involved adjacent skeletal muscle (11 cases) and tendon (three cases). Extensive epidermal ulceration was typically absent. Microscopically, the lesions had a lobular configuration. They were characterized by zones of fibrinoid necrosis and a prominent myxoid stroma rimmed by ingrowing, ectatic, thin-walled vascular channels. All cases contained atypical, enlarged, degenerated fibroblasts with abundant basophilic cytoplasm, large hyperchromatic, smudged nuclei, and prominent nucleoli; these features resulted in a superficial resemblance to proliferative fasciitis. The enlarged, atypical fibroblasts stained diffusely and strongly for vimentin (15 of 15 cases) and focally for muscle-specific actin (10 of 15 cases), keratin (one of 15 cases), CD68 (10 of 15 cases), and CD34 (five of nine cases) antigens; none of the cases stained for desmin. A malignant diagnosis was considered in 43% of cases. Follow-up in 21 patients ranged from 2 to 78 months (median, 12 months). Two lesions recurred once, one recurred twice, and none metastasized; no deaths were attributable to the lesions. The clinical, histologic, and immunohistochemical features of atypical decubital fibroplasia indicate it is a unique type of pressure sore displaying degenerative and regenerative features distinct from decubitus ulcer. Its recognition by pathologists and clinicians in elderly and debilitated patients is important to avoid misdiagnosis as a sarcoma and to prevent or minimize the occurrence of decubital fibroplasia in progressively aging patient populations.