Primary malignant fibrous histiocytoma (fibrous xanthoma) of bone

Inflammatory Malignant Fibrous Histiocytoma of the Kidney: An Immunohistochemical and Ultrastructural Study

A primary inflammatory malignant fibrous histiocytoma of the kidney is reported. The differential diagnosis from other sarcomas and pseudosarcomatous lesions is discussed on the grounds of the histologic, immunohistochemical and ultrastructural results. The neoplasm was made up of histiocytes, fibroblasts, myofibroblasts, foam cells and undifferentiated mesenchymal cells with admixed granulocytes, lymphocytes and plasma cells. The immunohistochemical study showed a positivity for alpha-1-antichymotrypsin and a weak positivity for alpha-1-antitrypsin in mononuclear and pleomorphic multinucleated tumor cells. PASpositive, diastase-resistant intracytoplasmic hyaline globules in necrotic cells, examined by electron microscopy, most likely represent lysosomal structures, in accordance with the theories of De Duve, Vattiaux and Von Ardenne.

Malignant Fibrous Histiocytoma of Bone: An Ultrastructural Study

An ultrastructural study of a case of malignant fibrous histiocytoma of bone in a 16-year-old skeletally mature female is presented. There were multiple metastatic bone lesions and a marked hypercalcemia. The cell population was similar to that found in soft tissue malignant fibrous histiocytoma lesions and comprised undifferentiated cells, fibroblastlike cells, histiocytes, and multinucleated giant cells. Occasional myofibroblasts and transitional cells with histiocytic and fibroblastic components were seen. The histiocytes were characterized by prominent Golgi bodies. Although there were many fibroblastlike cells, the rough endoplasmic reticulum was rarely as extensive or as well organized as in normal fibroblasts. The giant cells did not have the ultrastructural characteristics of osteoclasts, i.e., the clear zones and ruffled borders. Zonula adherens (belt desmosome) junctions were seen, but in general, intercellular junctions were poorly developed as to length and extent.

Malignant fibrous histiocytoma of the mandible

We report a case of malignant fibrous histiocytoma (MFH) primary within the mandible of a 32-year-old female. The mandible is a rare location of MFH, accounting for only 3% of all tumours of this type occurring within bone. The clinical, pathological and radiographic features are discussed with special emphasis on the radiographic features of this lesion.

Malignant fibrous histiocytoma of bone: a retrospective EMSOS study of 125 cases. European Musculo-Skeletal Oncology Society

In an effort to learn more about malignant fibrous histiocytoma (MFH) of bone and its prognosis with different treatment approaches, the European Musculo-Skeletal Oncology Society (EMSOS) initiated a retrospective survey among its members. Data requested included patient and treatment variables and outcome. The information on all patients with histologically proven, primary, localized osseous extremity MFH was analyzed if surgical tumor removal was performed and disease status was documented for at least one follow-up date. 125 such patients were evaluable (74 male, 51 female; median age 34 years; tumor site femur 81, tibia 26, humerus 12, other 6). Local treatment was surgery only (110) or surgery plus radiotherapy (15). Chemotherapy was used in 97/125. On last follow-up, 85 patients remained in remission, 33 had developed metastases, 6 a local recurrence, and 1 a combined relapse. With a median follow-up of 3.9 years for patients at risk, actuarial 5-year disease-free survival was 59%. In univariate analyses, younger age and the use of chemotherapy were associated with a more favorable outcome, as was limb-salvage surgery. 23 of 66 tumors with information on response to preoperative chemotherapy responded well (> 90% necrosis). Among these 23, only one relapsed.

Prognostic factors of malignant fibrous histiocytoma of bone. A clinical and histopathologic analysis of 34 cases

BACKGROUND

Malignant fibrous histiocytoma (MFH) of bone is a rare bone tumor, and its prognosis has been controversial.

METHODS

Thirty-four patients with MFH of bone were examined clinicopathologically for prognostic factors.

RESULTS

The most common skeletal site of the tumor was the femur (15 cases), followed by the pelvic bones (6 cases), tibia (5 cases), and fibula (5 cases). Of 29 patients available for follow-up, the 5-year survival rate of 17 who underwent adequate surgical treatment was 63%. The 5-year survival rate of the remaining 12 patients, including 5 with MFH of the pelvic bone who received inadequate or palliative surgery, was 17%. All six patients who received intensive chemotherapy combined with adequate surgical treatment were alive and well 5 years after the initial treatment. Histologically, the presence of desmoplasia and chronic inflammatory infiltration in the tumor tended to be prognostic indicators, although not to a statistically significant extent. Patients whose tumors contained wide areas of desmoplasia had a worse prognosis (5-year survival rate, 20%). In contrast, those with a prominent chronic inflammatory infiltrate had a 5-year survival rate of 78%.

CONCLUSIONS

These histologic variables would be helpful for predicting the prognosis of MFH of bone. Adjuvant intensive chemotherapy combined with adequate initial surgery may effect a clinical cure.

Chemotherapy of malignant fibrous histiocytoma of bone

BACKGROUND

Malignant fibrous histiocytoma of bone (MFHB) is a rare tumour with a 3 year survival of 30%-40% when treated with surgery alone. A small number of patients have previously been treated with pre-operative chemotherapy and responses observed. The aim of the present study was to further determine the response of MFHB to pre-operative chemotherapy.

PATIENTS AND METHODS

A non-randomised study of 18 patients with MFHB. Twelve had localised disease and 6 had pulmonary metastases. In 14 patients pre-operative treatment consisted of methotrexate 8 g/m2 on day 1, ifosfamide 3 g/m2 and doxorubicin 60 mg/m2 on day 10. This regimen was given twice and twice post-operatively. A further 4 patients received cisplatin 100 mg/m2 on day 1 and doxorubicin 25 mg/m2 on days 1, 2, 3. Three cycles were given pre- and post-operatively.

RESULTS

15 patients had surgery after chemotherapy. Tumour necrosis was present in all resection specimens and ranged from 50%-100%. 7/15 had > 90% necrosis. Disease free survival is 82% for those patients with a greater than 2 year follow-up.

CONCLUSION

This study confirms previous reports that MFHB is a chemosensitive tumour. In view of its rarity collaborative trials are needed to establish the optimum drug treatment including drug selection dose and duration.

Malignant fibrous histiocytoma of bone

Malignant fibrous histiocytoma (MFH) of bone is a malignant primary bone tumour that is being increasingly recognised, as more details emerge in the literature regarding its natural history and precise (although sometimes diverse) histological appearance. When the whole bulk of a malignant bone tumour fits the criteria laid down, the designation of MFH seems appropriate. Seven cases of MFH of bone were encountered from a total of 220 primary malignant bone tumours in our files over a 4-year period. The metaphyses of long bones were the most common sites harbouring the tumour, and a wide age range was represented. Amputation was the treatment of choice in all cases. The relevant literature is reviewed.

Malignant fibrous histiocytoma of the mandible

Malignant fibrous histiocytoma of the mandible has appeared frequently enough in the world literature in recent years to assume a legitimate place in the differential diagnosis of neoplastic masses of the lower jaw. This article reports a pertinent case and tabulates and correlates the findings of all cases reported thus far. The report also explores the contribution of immunohistochemistry to proper diagnosis and emphasizes the advantages of a cojoint effort between surgeon and pathologist at the time of initial patient evaluation. The case reported also demonstrates the poor prognostic characteristics of this lesion and the uncertainty as to proper mode of treatment.

Flow cytometric DNA analysis of bone tumors

Flow cytometric DNA analysis was performed in a total of 203 bone tumors, benign and malignant. In more than 80% of cases the material studied was paraffin-embedded tumor tissue, mainly from the archives of the Bone Tumor Registry of Westphalia in Münster. Compared with ethanol-fixed fresh tumor samples, the variation coefficient in DNA histograms of the stored material was increased by a factor of 1.2-1.5, which means that resolution was decreased and that, in many cases, accurate cell cycle analysis was not feasible. However, the results of cell cycle analysis in bone tumors, even if performed on optimally fixed specimens, have to be evaluated with caution and full reference to the corresponding histological slides, since these histograms are apt to show various superpositions from the inflammatory infiltrate. The assessment of DNA ploidy is unimpaired if, in agreement with most researchers today, deviations smaller than +/- 10% from the diploid standard are still defined as DNA diploid, peridiploid, or pseudodiploid. The coefficient of variation should be kept as low as possible. If it is between 10% and 15%, the near-diploid stemlines with DNA indices of 0.9 or 1.1 may be hard to delineate. On account of the particularly marked regressive changes, the resolution of DNA histograms was most strongly impaired in chondromatous tumors, whereas it was mostly excellent in highly cellular viable tumor tissue, such as that from Ewing's sarcoma or osteoblastoma. On the whole, there was a distinct correlation between DNA ploidy and the biological behavior of bone tumors (Table 8). The highest rates of DNA aneuploidy were found in highly malignant OSs (18/21) and FSs (14/16), thus reflecting their poor prognosis. Of six juxtacortical OSs, three well-differentiated parosteal OSs and two periosteal OSs were DNA diploid, whereas one highly malignant surface OS and five highly malignant extraskeletal OSs, all DNA aneuploid, corresponded fully to the medullary OSs. Judging by preliminary results, adjuvant preoperative chemotherapy (COSS 80/82: Bösing et al. 1987) may reduce the rate of DNA aneuploidy and, consequently, of stem cell heterogeneity in general. A selective destruction of those stemlines that respond particularly to chemotherapy appears probable. In contrast to their high malignancy, Ewing's sarcomas showed an unexpectedly low proportion of DNA aneuploid stemlines (14/24). The comparatively favorable prognosis of MFH of bone is reflected in a lower rate of aneuploidies (2/10), which is also rather low (probably too low) when compared to our own data from soft tissue MFH (9/19).(ABSTRACT TRUNCATED AT 400 WORDS)

An unexpected cause of pathologic hip fracture. Malignant fibrous histiocytoma

We describe a case of a 68-year-old patient presenting with pathological hip fracture and multiple pulmonary metastases, who has been operated without a prior histological diagnosis. The hip lesion was thought to be a metastasis of an unknown primary tumor. The proximal part of the femur was resected and replaced by a Müller mega-prosthesis. Histological analysis of the resected bone revealed a malignant fibrous histiocytoma, a rare but very aggressive bone tumor. The patient died three weeks after operation of widespread metastases. By presenting this case report, we want to stress the importance of pretreatment histological diagnosis of osteolytic bone lesions in older patients with metastases.

Osteosarcoma and the role of fine-needle aspiration. A study of 51 cases

Fifty-one patients were evaluated by fine-needle aspiration (FNA) as part of the diagnosis, staging, and management of osteosarcoma. All patients had histologic confirmation of osteosarcoma. Five patients underwent two aspirations each; thus, the total number of aspirates reviewed was 56. Aspirations were performed by interventional radiologists using fluoroscopic guidance. The cytologic features of osteosarcoma were divided into five groups: (1) pleomorphic (malignant fibrous histiocytoma-like); (2) epithelioid; (3) chondroblastic; (4) small cell; and (5) mixed. Although osteoid-like material was seen, it could not be distinguished readily from dense collagen. The chondroid matrix of chondroblastic osteosarcoma was recognized as a granular film with scattered clear bubbles. Fine-needle aspiration was diagnostic of sarcoma in 45 of 56 aspirates (80.4%). In eight aspirates, the cellularity of the smears was insufficient for diagnosis due to extensively osteoblastic tumors (six), necrotic tumor (one), and undetermined causes (one). In three aspirates, failure was attributed to poor cellular preservation due to unknown factors. The authors conclude that FNA is a useful tool in the multidisciplinary diagnosis and management of osteosarcoma. Aspirates should only be evaluated with full knowledge of the clinical and radiographic findings. The most significant limitation of FNA is the inability to detect osteoid.

Primary leiomyosarcoma of bone. A clinical, radiographic, pathologic-anatomic, and prognostic study of 16 cases

Sixteen cases of primary leiomyosarcoma of bone are described. The patients, 11 males and 5 females, ranged in age from 9 to 74 years. The annual incidence of this tumor in Sweden was calculated to be 0.09 cases per million. This figure was obtained by reviewing a Swedish series of spindle cell sarcomas of bone of which one quarter (11/44) were diagnosed by us as primary leiomyosarcoma. The diagnosis was based on light- and electron-microscopic examinations using the same criteria as for leiomyosarcoma of soft tissues. Thirteen tumors were located in a long bone of an extremity (nine close to the knee joint) and three in the central skeleton. Radiographically, all the tumors presented as a purely osteolytic lesion, and three patients had sustained a pathologic fracture. In four of six cases angiography suggested malignancy by revealing hypervascularity, irregular tortuous vessels, and diffuse contrast opacification. Contrast-enhanced computed tomography, performed in two cases, showed hypervascular areas within the tumors. Scintigraphy showed a marked increase in radionuclide uptake in all five cases studied. The clinical behavior indicates that primary leiomyosarcoma of bone is highly malignant. Eight patients had died of the tumor and, of the eight patients who were alive at follow-up, two had metastases, and one had been operated on three times for a cutaneous metastasis, which had recurred locally twice. The remaining five patients had been continuously free of disease for 6.5 to 12.3 years.

Malignant fibrous histiocytoma involving a digit

A case of malignant fibrous histiocytoma (MFH) involving phalanges of a single digit is reported. MFH of the bones of the hand has not previously been reported. Ten years after wide local excision, the patient remains clinically free of disease.

Malignant fibrous histiocytoma of jaws. A clinicopathologic study of 11 cases

Malignant fibrous histiocytoma (MFH) of the jaws is a highly malignant tumor that recurs, metastasizes, and usually causes death despite aggressive surgical therapy. This clinicopathologic review looks at five patients with MFH of the maxilla and six with MFH of the mandible. Five male and six female patients ranged in age from 12 to 75 years (mean, 35.4 years). All patients had large lytic areas of bone destruction, often with soft tissue extension. Two cases were postirradiation sarcomas, one of the maxilla and the other of the mandible. All patients underwent surgery and eight patients received chemotherapy when disease recurred locally or metastasized. Seven patients had local recurrences 3 to 13 months following surgery, and six patients had distant metastases. Of the 11 patients, 7 died of their disease, 1 died of unknown causes, and another with extensive local disease was lost to follow-up after 1.7 years. Two patients with recurrent disease are alive at 18 and 27 months postoperatively.

Malignant fibrous histiocytoma of the maxilla. Case report and review of the literature

A case of malignant fibrous histiocytoma (MFH) occurring in the maxilla is presented. Although MFH is now recognised as the most common soft tissue sarcoma of late adult life, it rarely occurs in bone and then more usually in the long bones. Presentation affecting the facial bones and skull is extremely rare, but should be considered in the differential diagnosis of bone tumours affecting the maxilla. Skeletal lesions appear more aggressive than those in soft tissues. Early radical excision is the treatment of choice although radiotherapy for inoperable tumours may lead to regression, as in the case presented here.

Treatment of malignant fibrous histiocytoma of bone. A plea for primary chemotherapy

Seven patients have been treated for malignant fibrous histiocytoma (MFH) of bone since the end of 1977. One patient received no chemotherapy, and one did not complete attempted chemotherapy. Both died, 7 and 51 months after diagnosis, respectively. The remaining five patients completed chemotherapy. Two first underwent a primary amputation, whereas the other three received primary chemotherapy with histologic evaluation of the effect. These patients showed a complete remission. The five patients who completed chemotherapy are all still alive, without indications of metastases or local recurrence. Although the number of cases is small, a 25- to 58-months (mean, 45) survival, in five patients treated either with chemotherapy alone or chemotherapy and surgery, is surprisingly good in view of previous experience with this tumor. In some of these patients, the authors were able to document an absence of any viable tumor following chemotherapy.

Malignant fibrous histiocytoma of bone. A review of 13 cases and an ultrastructural study

Observations on 13 patients with primary malignant fibrous histiocytoma of bone were reported. Included were nine male and four female patients, ranging in age from 6 to 81 years (mean, 44.8 years). Pain was the most common complaint. The interval from the first symptom to the initial treatment varied from 2 months to 20 years. Seven tumors arose in the knee region. Roentgenologically, most of the lesions presented with an osteolytic and destructive appearance. Histologically, highly variable morphologic features existed. The storiform-pleomorphic pattern was found in every tumor, although it was not necessarily pathognomonic for malignant fibrous histiocytoma of bone. Surgery, radical or incomplete, was the primary treatment for all but one patient. Lymph node metastasis was present in three. Five patients died of the disease from 3 to 79 months after the diagnosis (mean, 28 months), all exhibiting metastasis to the lung. Gaucher's body-like structure demonstrated in the electron microscopic study shows the histiocytic quality of malignant fibrous histiocytoma of bone.

Radiology and pathology of malignant fibrous histiocytomas of the soft tissues: a report of ten cases

Malignant fibrous histiocytomas (MFH) are believed to originate from histiocytes and are composed of malignant cells with spindle or round shapes. We evaluated ten MFH of the soft tissues by plain roentgenograms, computed tomography (CT), and angiography and subdivided them into four grades of anaplasia and five predominant histologic variants. The variants of MFH demonstrated different vascular patterns. The extension of the lesions could be determined by CT and angiography. CT is the method of choice in the assessment of size and extent of MFH of the soft tissues. When intra-arterial chemotherapy is indicated the angiograms obtained at each catheter placement may substitute CT in follow-up studies obviating additional diagnostic procedures.

Malignant fibrous histiocytoma of bone. The experience at the Rizzoli Institute: report of 90 cases

Ninety cases of malignant fibrous histiocytoma (MFH) of bone are reported. An analysis is presented with regard to sex, age, site, symptoms, radiography, macroscopic, and microscopic features. The staging was assessed according to the following classification: I B: 3 cases; II A: 11 cases; II B: 66 cases; III: 10 cases. Among nonmetastatic patients, 68 had surgical treatment (adequate, 46; inadequate, 22); 8 had radiotherapy, and 3 refused any treatment. Among surgically treated patients, 20 had adjuvant chemotherapy, also. Follow-up information was obtained in all cases. Overall survival rates were 34% at 5 years, and 28% at 10 years. Surgery alone did not appear to be successful (5-year survival, 28%). Adjuvant chemotherapy improved the survival rate only in patients who underwent adequate surgery (5-year survival, 57%). The recurrence rate after surgical treatment was high (31%) with significant differences after inadequate (64%), wide (19%), or radical (6.5%) surgical treatment. Adjuvant chemotherapy was ineffective in preventing local recurrence. Radiation therapy effected a clinical cure in three cases; the authors believe that radiation therapy has to be used only in inoperable tumors.

Fibrosarcoma and malignant fibrous histiocytoma of long bones: radiographic features and grading

The salient radiological features of 102 cases of fibrosarcoma and of so-called malignant fibrous histiocytoma (MFH) of the long bones are presented. All cases registered with the Netherlands Committee on Bone Tumours in the period 1953-1976, were originally classified as fibrosarcoma. In a recent review of the pathological material approximately half of these tumours were reinterpreted as malignant fibrous histiocytoma. As the two neoplasms demonstrate no difference in their clinical picture, radiological appearance, and survival statistics, we did not study both groups separately. Favourable radiographic signs which suggest a longer survival rate included: a geographic type of bone destruction, eccentric location, and cortical destruction involving no more than two quadrants of the bone circumference. Based on these findings a grading system is presented which differs from that proposed by Lodwick et al. [21].

Chemotherapy of malignant fibrous histiocytoma of bone. A report of five cases

Five patients with evaluable malignant fibrous histiocytoma (MFH) of bone (three with primary tumor and two with primary tumor and metastatic disease) were treated with preoperative chemotherapy including high dose methotrexate (HDMTX) with citrovorum factor rescue (CFR) as is used for patients with osteogenic sarcoma. All five patients demonstrated a clinical response to chemotherapy. Three of four patients who underwent surgery had complete responses and one patient had greater than 90% tumor necrosis as documented by histologic examination of the resected primary tumor. All four patients who underwent surgery following preoperative chemotherapy are surviving free of disease from one to six years from the start of treatment; chemotherapy was discontinued after six to 11 months in these patients. The median disease-free survival time is 31.5 months. This study demonstrates the effectiveness of chemotherapy in MFH of bone, and in particular the effectiveness of HDMTX with CFR which caused measurable responses in all patients while receiving this therapy as a single agent.

Adjuvant chemotherapy of malignant fibrous histiocytoma of bone

Malignant fibrous histiocytoma (MFH) is a pleomorphic sarcoma that is uncommon in children. It most frequently arises from the soft tissues; however, it has been recently established that primary bone MFH also exists. Surgical resection or amputation is the cornerstone of treatment for MFH of bone. But, with this modality of therapy alone the majority of patients develop either distant metastases or local recurrence. This study reports on three adolescent girls with MFH of bone who were successfully treated with radical resection and 18 months of adjuvant chemotherapy with vincristine, high dose methotrexate, Citrovorum Factor rescue, and Adriamycin. All three patients remain disease-free for a follow-up period of 42-48 months. The current regimen was well tolerated. Morbidity was minimal, with no patient developing any significant drug-related complications. The adjuvant chemotherapy regimen described appears to be effective in prolonging survival in patients with MFH of bone and appears to warrant further study in additional patients.

Experimental studies on malignant fibrous histiocytomas in rats. I. Production of malignant fibrous histiocytomas by 4-hydroxyaminoquinoline 1-oxide in bone of Fischer 344 strain rats

Malignant fibrous histocytomas (MFHs) were induced by a single injection of 4-hydroxyaminoquinoline 1-oxide (4-HAQO) into periosseous tissue of the tibia or by inserting solid 4-HAQO into the bone marrow of the tibia of male Fischer 344 rats. Periosseous MFHs were induced by doses of 2 mg and 4 mg of 4-HAQO per rat in three of 13 (23%) rats and nine of 13 (69%) rats, respectively, at 18 to 27 weeks after treatment. Bone MFHs were induced by doses of 2 mg, 4 mg, and 8 mg of 4-HAQO per rat in one of 15 (7%) rats, 11 of 18 (61%) rats, and 12 of 14 (86%) rats, respectively, after 18 to 29 weeks. Radiologic examination of bone MFH revealed bone destruction with or without a periosteal reaction, pathologic fracture, and tumor invasion into periosseous soft tissue. The serum alkaline phosphatase levels were elevated in rats with bone MFHs. Histologically, these MFHs were divided into fibrous, giant cell, myxoid, and inflammatory types. The incidence of fibrous MFHs was highest. Lung and inguinal and/or retroperitoneal lymph node metastases were observed in some rats, and these were of the fibrous type. These MFHs were quite similar to those in humans histologically and electron microscopically. This work establishes an animal model for studying the pathogenesis of bone MFH.

Primary malignant fibrous histiocytoma of bone: report of six cases with ultrastructural study and analysis of the literature

Six cases of malignant fibrous histiocytoma (MFH) primary in bone were studied clinicopathologically with ultrastructural study of three. The histologic differentiation of MFH from osteosarcoma and from fibrosarcoma is discussed. Two of the six cases had highly malignant tumors histologically designated as Grade III and IV; one died with diffuse metastatic disease eight months after diagnosis and the second developed pulmonary metastases within ten months. Review of the literature revealed that 45 of the total 119 reported cases had been followed for less than five years; these cases were considered unevaluable for assessing biologic behavior. The remaining 74 cases, followed for more than five years or until death, showed a 36.5% five-year survival rate. All but one of the cases which developed metastasis within five years did so within the first two years. It is therefore concluded that MFH of bone is a rapidly metastasizing tumor with a relatively low five-year survival rate. Paradoxically, 13 of these 74 cases (17.6%) survived between five and 38 years with no evidence of disease. This is comparable to the long-term survival rate in osteosarcoma. The five-year survival rate is also comparable to that of fibrosarcoma of bone.

Malignant fibrous histiocytoma of bone. A clinico-pathological and electronmicroscopical study

The clinicopathological and ultrastructural features of seven Malignant Fibrous Histiocytomas reported to the Spanish Registry of Bone Tumors were studied. Two patients were females (20 and 60 years old) and the other five males (15, 37, 67, 38 and 17 years old). The tumors were located in the lower femur (3 cases), upper tibia, upper humerus, rib and iliac bone. The past medical history revealed previous fracture in one patient and previous radiation of the affected bone in another; in a third patient the tumor associated to a bone infarct. Microscopically all tumors presented a storiform pattern composed of neoplastic fibroblasts, histiocytes, and malignant multinucleated giant cells. There was no evidence of osteoid or bone tissue formation by the tumor cells. Five cases were studied with electronmicroscopy; the tumor cells had features of fibroblasts, myofibroblasts, histiocytes and multinucleated histiocytes. Primary and secondary lysosomes, along with lipid vacuoles were common findings in the tumor cells. The value of the electron-microscopy in the differential diagnosis of this tumor is emphasized.

Malignant fibrous histiocytoma of bone. Light microscopic and electron microscopic examination of four cases

Malignant fibrous histiocytoma (MFH) of bone is a well-defined tumor by light microscopy but no agreement has been achieved concerning its histogenesis. We present the light and electron microscopic findings of four cases of MFH of bone. In case 1 multiple bone tumors were observed and in case 4 the tumor developed after irradiation. It was our aim to document the cytological variability and to arrange the findings in a histogenetic concept of primary intraosseous MFH. We observed some undifferentiated cells but mainly histiocyte- and fibroblast-like cells including intermediate forms, and several types of giant cells. We should emphasize the fact that there were also some large cells with a light microscopic resemblance to rhabdomyoblasts and with electron microscopic characteristics of myoblastic differentiation. From the ultrastructural point of view, therefore, MFHs seem to derive from a primitive mesenchymal stem cell rather than from the ordinary histiocyte. It is suggested that osteosarcoma and MFH of bone may have a common progenitor cell but it is important to make a clear clinico-pathological distinction between the tumors because of differing biological behavior.

Non-epithelial tumors of the nasal cavity, paranasal sinuses and nasopharynx: a clinico-pathologic study XI. fibrous histiocytomas

As part of our review of non-epithelial tumors involving the nasal cavity, paranasal sinuses, and nasopharynx, nine fibrous histiocytomas (FH) are reported. FH probably are derived from undifferentiated mesenchymal stem cells that have the ability to differentiate into two different pathways, one fibroblastic and the other histiocytic. The proportion of these two different elements varies greatly in different lesions. The cell population ranges from cytologically benign (small bland nuclei and no mitoses) to overtly malignant (marked anaplasia and numerous mitoses). Based on our cases and on 12 previously reported tumors, FH involving the upper respiratory passages may cause clinical problems similar to those produced by other soft tissue neoplasms affecting this area, (nasal obstruction, a mass or swelling in the involved area, epistaxis, loosening of teeth, or facial pain). Physical examination may show a mass projecting into the nasal, sinus, or oral civity; facial asymmetry; proptosis; or a periorbital mass. Radiographic studies may demonstrate sinus opacification or cloudiness, a mass, or bone destruction. Treatment has included polypectomy, wide local excision, partial maxillectomy, or radical maxillectomy, depending on the size and extent of the lesion. When involving the upper respiratory passages, FH, if incompletely excised, may recur locally, requiring a more extensive resection. A minority of these tumors have metastasized via lymphatic and/or venous channels. Histologic features appear to correlate with clinical course.

Fibrous histiocytoma (fibroxanthoma) of a cervical vertebra. A report with a review of the literature

A patient with a benign appearing intraosseous fibrous lesion of the cervical vertebra is presented. The lesion had the histologic features of non-ossifying fibroma (metaphyseal fibrous defect). Because of its atypical location and unusual radiologic appearance, the lesion was diagnosed as a fibrous histiocytoma, a tumor whose histology is similar to non-ossifying fibroma. The literature was reviewed for similar cases located outside the metaphysis of the long bones. Support is given for designating such lesions as fibrous histiocytomas rather than non-ossifying fibromas.

Malignant fibrous histiocytoma of bone: a study of 35 cases

Thirty-five cases of primary malignant fibrous histiocytoma of bone are reported. Twenty of these cases were collected from a retrospective analysis of other malignant bone tumors. The age range was from 11 to 69 years; the average age was 34 years. The tumor occurred most commonly in the distal femur and proximal tibia. The distinguishing histologic feature was a storiform arrangement of spindle cells. The differential diagnosis included fibrosarcoma, osteogenic sarcoma, malignant giant cell tumor, malignant lymphoma, and metastatic carcinoma. Follow-up of at least three years was available in 21 cases. Of these, nine patients were alive and free of metastases three and one-half to 12 years after treatment. Two were alive with solitary metastases at three years, and 10 patients died between three months and three years after treatment. In four cases the lesions were multicentric at the time of diagnosis and in four cases were associated with bone infarction. This tumor must be recognized as an important complication of bone infarction and should be suspected when a patient with a known history of bone infarction develops a change in symptoms. Because the prognosis of this tumor is significantly better than that in those tumors with which it had been previously grouped, and in view of its association with bone infarction, it deserves to be maintained as a distinct clinicopathologic entity. Amputation is the treatment of choice.

Malignant fibrous histiocytoma (malignant fibrous xanthoma: xanthosarcoma) of bone

Seven cases of malignant fibrous histiocytoma of bone are documented. In addition to typical histologic features such as the presence of a storiform pattern, histiocytic and fibrocytic cell types and severe cellular atypism, in five cases there were areas in which osteoclast-type giant cells were prominent and the lesion resembled a giant cell tumor. Three of the seven patients developed pulmonary metastases within two years of amputation, one developed extensive local recurrence including soft tissue and vascular invasion, and the other three are without evidence of disease but have been followed for only short periods.