John W. Beabout

Chordomas and cartilaginous tumors at the skull base.

Special attention was given to chordomas and all cartilaginous tumors at the base of the skull during a study of the clinical and pathologic data on 155 chordomas (76 sacrococcygeal, 55 spheno‐occipital, and 24 vertebral) seen at the Mayo Clinic. Attention also was drawn to a histologically separate group of spheno‐occipital chordolmas which comprised one third of the tumors in this location and was associated with a surprisingly better prognosis. These tumors, which may bear a striking histologic resemblance to chondrosarcomas or chondromas, had clinical and roentgenologic features that convinced us of their kinship to ordinary chordomas and led us to designate them as “chondroid” chordomas. When these were excluded from the cartilaginous tumors of the base of the skull, there remained only four such tumors, all chondrosarcomas, in the files of the Mayo Clinic. Thus most of the chondrosarcoma‐like tumors of the base of the skull have a paradoxically indolent course. Assessment of long‐term survival patients indicated that extensive surgical resection combined with irradiation offers the best palliation and prolongation of life.

Dedifferentiation of low‐grade chondrosarcomas

Of 370 well‐differentiated chondrosarcomas, 33 had dedifferentiated zones of fibrosarcoma or osteogenic sarcoma. The clinical characteristics, including long preoperative duration of symptoms, age distribution of patients, and skeletal localization, and certain roentgenographic features correlated well with the chondrosarcomatous component of these tumors. The rapid deterioration of most of the patients after operation was determined by, and characteristic of, the anaplastic portion of the tumor and indicated the need for radical treatment at the earliest practicable date.

Bizarre parosteal osteochondromatous proliferations of the hands and feet.

ABSTRACTWe report 35 cases of peripheral skeletal osteochondromatous tumefactions which are both histologically and radiologically distinctive. The ages of the patients ranged from 14 to 74 years, with no sex predilection. Symptoms were related to the tumefaction. None of the patients had antecedent physical trauma or radiation. All lesions occurred on proximal phalanges, metatarsals, or metacarpals. Primary treatment was usually excision, and the gross appearance was typically that of a small osteochondroma. Histologically, the lesion exhibited marked proliferative activity, irregular bony-cartilaginous interfaces, and enlarged, bizarre, and binucleate chondrocytes, mimicking chondrosarcoma. Radiologically, the proliferations lacked both central continuity of the tumor with the underlying osseous medulla and “flaring” of the adjacent cortices. In 18 cases, the lesions recurred after primary excision, and at least eight lesions recurred twice. In spite of the rate of recurrence and the disturbing histologic appearance of these proliferations, behavior as a malignant tumor is either very rare or nonexistent.

Hemangioma, hemangiopericytoma, and hemangioendothelioma (angiosarcoma) of bone.

Sixty‐nine cases of bone tumors of vascular origin, excluding cases of lymphangiomas and massive osteolysis, were found in a complete review of the surgical files of the Mayo Clinic. There were 56 hemangiomas, and these often produced roentgenologic diagnostic problems. Most were easily managed surgically, although some vertebral hemangiomas required radiation therapy. There were known multicentric lesions in only 2 of the 56 cases. Hemangiopericytomas accounted for 4 of the 69 cases. In these 4, the clinical courses were characteristically unpredictable. There were 9 hemangioendotheliomas. These 9 were added to 13 cases in which specimens were submitted for review. In 6 of the 22 cases, there was multifocal involvement. In this group of 22 cases, it was impractical to differentiate a separate group and designate it as angiosarcoma. Half of the 22 patients died, 1 of known unrelated disease. Surgical extirpation, when possible, and irradiation of lesions incompletely excised or surgically inaccessible seem logical principles in treatment. In these cases of hemangioendotheliomas, the most important indicator of prognosis was the grade of anaplasia.

Chondromyxoid fibroma: A clinicopathologic study of 76 cases

A study of 76 chondromyxoid fibromas affirms that it is a benign tumor, apparently of cartilaginous derivation, that is most likely to occur in adolescents and young adults. Although a wide skeletal distribution has been observed, the lesion most often affects major limb bones, especially the tibia. The characteristic but somewhat complex histologic range of this lesion, coupled with its benign appearance on roentgenograms, allows ready distinction from other tumors, most importantly chondrosarcoma. The lesion is somewhat more aggressive and considerably more likely to recur in young patients, but adequate local resection nearly always can forestall such recurrence. Malignant transformation is extremely improbable.

Parosteal osteogenic sarcoma.

A clinicopathologic study of 79 patients with parosteal osteogenic sarcoma revealed that more females than males were affected and that most of the patients were in the second to the fourth decades of life. Sixty‐eight percent of the patients had involvement of the posterior aspect of the lower femoral shaft. The roentgenogram characteristically showed a large, dense lobulated mass attached by a broad base to the underlying bone but with no involvement of bone itself. Microscopically, the tumor presented as well‐formed bands of osteoid within a hypocellular spindle cell stroma. Seven of the lesions had foci of high‐grade osteogenic sarcoma within an otherwise typical parosteal osteogenic sarcoma. Six of the 79 lesions showed involvement of the medullary cavity at surgery. Thirty‐one patients had excision as their initial treatment; four of the 31 required no further therapy. Ten patients had resection initially; three of the ten had recurrence. Only four of 27 patients who underwent amputation initially developed pulmonary metastasis. The presence of histologically “active” tumor and medullary involvement seemed to affect the prognosis adversely. Our data indicate that complete radical removal of the the tumor is the treatment of choice, with resection when feasible and amputation when necessary.

Parosteal osteosarcoma. A clinicopathological study.

The records of 226 patients (sixty-seven who were managed at our institution and 159 who were identified from the consultation files) who had had a parosteal osteosarcoma were reviewed. The criteria for diagnosis were that, roentgenographically, the lesion had arisen from the surface of the bone and that, histologically, the tumor was well differentiated (Grade 1 or 2); it was characterized by well formed osteoid within a spindle-cell stroma; and, when there was medullary involvement, less than 25 per cent of the medullary cavity was affected. Dedifferentiation was more common (16 per cent of the patients) than previously reported and was associated with a poor prognosis. Cross-sectional imaging studies demonstrated medullary involvement in 22 per cent of the patients, an unmineralized soft-tissue mass peripheral to the mineral component in 51 per cent, and adjacent soft-tissue invasion in 46 per cent. In contrast to the findings in our previous studies, medullary involvement was not a poor prognostic factor. At an average of thirteen years (range, two to forty-one years), eleven of the sixty-seven patients who were managed at our institution died of the tumor; ten of these patients had a dedifferentiated tumor. Statistical analysis of the thirty-nine patients who had had the primary treatment at our institution revealed that incomplete resection was associated with an increased risk of local recurrence and that dedifferentiation markedly increased the risk of metastasis.

Chondromyxoid fibroma of bone: A clinicopathologic review of 278 cases

In a study of the clinical, radiographic, and pathological features of chondromyxoid fibroma, the tumor was slightly more common in men, usually in the second decade of life. Almost half of the tumors involved the long bones, although the ilium and the small bones were also common sites. Roentgenograms showed a sharply marginated, lobulated, lucent defect in the metaphysis. The tumor involved the medullary bone in an eccentric fashion, and the cortex was thinned and expanded. Periosteal reaction and soft tissue extension were uncommon. Mineralization was identified in 13% of the lesions. Histologically, the tumors were almost always arranged in lobules, which were prominent (macrolobular) or somewhat indistinct (microlobular). The tumor cells were spindle-shaped or stellate and arranged in a myxoid matrix. Calcification was seen in more than one third of the cases but was rarely prominent. Hyaline cartilage and chondroblastoma-like areas were not uncommon. Approximately 18% of tumors showed bizarre nuclei. Permeation of bony trabeculae was uncommon. Treatment was conservative surgical removal; approximately one fourth of the patients had recurrence.

Periosteal osteogenic sarcoma

A study of 102 osteogenic sarcomas of the bone surface revealed that 79 were parosteal osteogenic sarcomas. Roentgenographically, these 79 were dense, lobulated lesions attached by a broad base to underlying bone, usually the lower femoral shaft. Histologically, they were low‐grade osteosarcomas. The other 23 lesions (periosteal osteogenic sarcoma) usually involved the upper tibial shaft and presented as small radiolucent lesions on the surface, with formation of spicules of bone perpendicular to the bone shaft. Histologically, these 23 were relatively high‐grade, predominantly chondroblastic osteogenic sarcomas. Thirteen of the 23 patients were males, and most were in the second decade of life. Of five patients who had excision of the tumor, three had recurrence. Of four patients who had resection of the tumor, two had recurrence. Seven of 13 patients who underwent amputation initially were alive without disease at last follow‐up. Only 4 of the 23 patients have died of metastatic disease.

Malignant giant cell tumor of the tendon sheaths and joints (malignant pigmented villonodular synovitis)

Malignant pigmented villonodular synovitis (PVNS) is a rare lesion whose existence may be debatable. We studied eight cases that we consider to be examples of malignant PVNS. The three male and five female patients were aged 12 to 79 years. The knee was involved in three cases; the ankle in two; and the cheek, dorsum of the foot, and thigh in one each. Four patients had swelling for 6 months to 17 years before presentation. Three cases of malignant PVNS were secondary, arising in patients in whom PVNS had been documented previously, and five cases were primary, with histologic features similar to those of the secondary ones. Important histologic features of malignancy were (a) a nodular, solid infiltrative pattern of the lesion; (b) large, plump, round or oval cells with deep eosino philic cytoplasm and indistinct borders; (c) large nuclei with prominent nucleoli; and (d) necrotic areas. Atypical mitoses were occasionally seen. Four patients died with pulmonary metastasis (two also had metastasis to inguinal lymph nodes). Four patients are alive from 3 1/2 to 5 years after the last surgical treatment. The malignant nature of this lesion, the histologic architecture similar to that of PVNS, and the fibrohistiocytic appearance of the cells suggest that malignant PVNS is an entity.