Xanthogranuloma of the rectum

A 46-year-old man with a suspected malignant submucosal tumor received a transabdominoperineal rectal amputation. The histologic diagnosis was xanthogranuloma. The differentiation of xanthogranuloma from malignant fibrous histiocytoma and other histiocytic tumors is difficult in the preoperative stage. Malignant fibrous histiocytoma can be diagnosed histologically by the presence of pleomorphism, mitotic activity, hyperchromatism, and a storiform pattern of cell arrangement. Moreover, some xanthogranulomas are also thought to have malignant potentiality and surgical resection is regarded as the preferred treatment. As for prognosis, the patient has lived for three years after the operation but further follow-up is thought to be necessary.     

Immunohistochemical identification of lysozyme in cutaneous lesions of alleged histiocytic nature

Histiocytosis X, multicentric reticulohistiocytosis, juvenile xanthogranuloma, the "fibrous" type of dermatofibroma, dermatofibrosarcoma protuberans, and malignant fibrous histiocytoma are all characterized by dermal and/or subcutaneous infiltrates composed at least partially of cells having morphologic features suggestive of histiocytes. Paraffin-embedded tissues representing these conditions were stained for lysozyme (muramidase) with a peroxidase-antiperoxidase technic. The cells of juvenile xanthogranuloma were rich in lysozyme. Some of the cells of histiocytosis X showed a positive pattern, and the cells of the other three conditions were essentially negative. This study confirmed the histiocytic nature of juvenile xanthogranuloma and multicentric reticulohistiocytosis, supported the interpretation that there is a histiocytic component in the lesions of histiocytosis X, and cast some doubt on the alleged histiocytic nature of "fibrous" dermatofibroma, dermatofibrosarcoma protuberans, and malignant fibrous histiocytoma.     

Malignant fibrous histiocytoma of bone and osteosarcoma. A comparative light and electron microscopic study.

Malignant fibrous histiocytomas are well-described tumors of the soft tissues. Recent investigations have shown that malignant histiocytoma may also occur as a primary bone tumor. However, difficulties may arise to distinguish malignant histiocytoma of bone from other malignant bone tumors, such as osteosarcoma. In the present study, the ultrastructure of five cases of malignant fibrous histiocytoma of bone is compared with that of osteosarcoma. The results show that malignant fibrous histiocytoma is composed mainly of histiocytic cells and fibroblastic cells. In addition, xanthomatous cells, undifferentiated cells, and giant cells may be observed. By contrast, the predominant cell type in osteosarcoma is the neoplastic osteoblast, characterized by abundant rough endoplasmic reticulum. Signs of matrix calcification in the intercellular matrix between the collagen fibrils are regularly observed in osteosarcoma, but not in malignant histiocytoma. From these results it is concluded that the ultrastructure of malignant fibrous histiocytoma arising in bone is morphologically identical with the soft tissue counterpart of this tumor. The components of the tumor are derived from neoplastic histiocytes. This cytogenesis differs from that of osteosarcoma, which is derived from neoplastic osteoblasts. Therefore, from the ultrastructural point of view, malignant fibrous histiocytoma of bone should be accepted as a distinct histologic entity among bone tumors.     

Immunohistochemical observation of intracytoplasmic lysozyme in proliferative and neoplastic fibrohistiocytic lesions

Distribution of intracytoplasmic lysozyme in proliferative and neoplastic fibrohistiocytic lesions and non fibrohistiocytic tumors was studied by immunoperoxidase technique on formalin fixed, paraffin-embedded sections. The cases examined were 161 fibrohistiocytic lesions and 86 non-fibrohistiocytic tumors. Contrary to our expectation, the lysozyme positive cells were found only in the minority of cases with fibrohistiocytic lesions. Cells positive for lysozyme were found only in 13 out of 100 cases of dermatofibroma, one out of 4 cases of xanthogranuloma and 8 out of 33 cases of malignant fibrous histiocytoma. Dermatofibrosarcoma protuberans and non-fibrohistiocytic tumors were negative for lysozyme. It is suggested that in proliferative fibrohistiocytic lesions, induction of lysozyme synthesis is weak or absent. Some malignant fibrous histiocytomas showed scattered lysozyme positive neoplastic cells, indicating their probable histiocytic origin or differentiation. On the other hand, evidence of histiocytic differentiation of dermatofibrosarcoma protuberans was not obtained using lysozyme immunohistiochemistry.     

IMMUNOHISTOCHEMICAL OBSERVATION OF INTRACYTOPLASMIC LYSOZYME IN PROLIFERATIVE AND NEOPLASTIC FIBROHISTIOCYTIC LESIONS

Distribution of intracytoplasmic lysozyme in proliferative and neoplastic fibrohistiocytic lesions and non fibrohistiocytic tumors was studied by immunoperoxidase technique on formalin fixed, paraffin-embedded sections. The cases examined were 161 fibrohistiocytic lesions and 86 non-fibrohistiocytic tumors. Contrary to our expectation, the lysozyme positive cells were found only in the minority of cases with fibrohistiocytic lesions. Cells positive for lysozyme were found only in 13 out of 100 cases of dermatofibroma, one out of 4 cases of xanthogranuloma and 8 out of 33 cases of malignant fibrous histiocytoma. Dermatoflbrosarcoma protuberans and non-fibrohistiocytlc tumors were negative for lysozyme. It is suggested that In proliferative fibrohistiocytic lesions, Induction of lysozyme synthesis is weak or absent. Some malignant fibrous histiocytomassh owed scattered lysozyme positive neoplastic cells, indicating their probable histiocytic origin or differentiation. On the other hand, evidence of histiocytic differentiaton of dermatofibrosarcoma protuberans was not obtained using lysozyme immunohistiochemistry.     

Disseminated malignant fibrous histiocytoma (giant cell rich): a case report

Giant cell rich malignant fibrous histiocytoma accounts for 3 -15% of all malignant fibrous histiocytomas. Currently, the nomenclature giant cell malignant fibrous histiocytoma is reserved for undifferentiated pleomorphic sarcomas with prominent osteoclastic giant cells. It is considered to be synonymous with malignant giant cell tumor of soft parts. We report a case of disseminated giant cell malignant fibrous histiocytoma involving the scalp, cervical node, lungs, spine, abdominal wall, base of penis, gluteal cleft, paraspinal region and back. The diagnosis was established after staining for a panel of immunohistochemical markers namely cytokeratin, vimentin, S100, desmin, CD68 and smooth muscle actin. CD68 positivity in tumor cells helped in arriving at the final diagnosis. It is essential to recognize this tumor as a giant cell rich distinct entity and differentiate from other giant cell rich pleomorphic sarcomas since therapeutic and prognostic differences are being appreciated currently.     

Malignant fibrous histiocytoma of the larynx]

A rare case of larynx malignant fibrous histiocytoma is presented. Histologically and ultrastructurally, the tumour was similar to malignant fibrous histiocytoma of other organs. The patient was followed up for 2 years after surgical treatment and preoperative irradiation. No recurrence and metastases were observed.     

Malignant fibrous histiocytoma arising in a recurrent chordoma

Summary We present the case of a sacrococcygeal chordoma which recurred 15 years after the radical removal as a soft tissue tumor in the gluteal musculature. This tumor consisted of two parts: a chordoma without symptoms of aggressive cellular proliferation and a malignant fibrous histiocytoma. During the following 4 years several local recurrences of the malignant fibrous histiocytoma occurred in the gluteal musculature. The patient finally died of lung metastases. No chordoma tumor tissue was found in the lungs, in the gluteal musculature or in the sacrococcygeal bone area. Histology including electron microscopy revealed no proof of a transition of chordoma into malignant fibrous histiocytoma. It must be assumed that the secondary soft tissue tumor originated from residual chordoma cells which were implanted during the operation of the primary tumor. It remains unclear whether the malignant fibrous histiocytoma arose from mesenchymal stromal cells within the chordoma or directly from primitive neuroectodermal chorda cells which possess the ability to differentiate into a variety of cell types including mesenchymal cells.     

Angiomatoid malignant fibrous histiocytoma

Angiomatoid malignant fibrous histiocytoma (MFH), is a rare but distinct fibrohistiocytic tumour of children and young adults, simulating a vascular neoplasm. A case of angiomatoid malignant fibrous histiocytoma in a 12 year old male is reported.     

Angiomatoid malignant fibrous histiocytoma

Summary A case of an angiomatoid malignant fibrous histiocytoma is presented. The electron microscopic findings demonstrate the presence of a variety of tumor cell types including smooth and striated muscle cells. This indicates that malignant fibrous histiocytoma originates from a pluripotent primitive mesenchymal cell.     

Primary pleomorphic malignant fibrous histiocytoma of the heart

Primary pleomorphic malignant fibrous histiocytoma of the heart is rare. The present study was performed to study the clinical and pathological features of the disease. We describe two rare cases of primary cardiac malignant fibrous histiocytoma and review the published individual data of the patients. Both patients complained of dyspnea, and underwent palliative tumor resection. However, they died several months after surgery. A thorough literature review with clinical presentations, diagnostic features, treatment, and outcomes was done. We have for the first time analyzed the factors related to the survival of malignant fibrous histiocytoma. It is usually difficult to make an appropriate preoperative diagnosis. Despite complete surgical resection and aggressive chemotherapy and radiotherapy, the prognosis is still poor.     

Mitochondria-Rough Endoplasmic Reticulum Complexes in a Malignant Fibrous Histiocytoma

Mitochondria-rough endoplasmic reticulum complexes identical to the ones usually found in chordoma were frequently observed in tumors cells of a malignant fibrous histiocytoma arising in the left thigh of a 48-year-old woman. Although the significance of these structures is unknown, this finding is consistent with the known transformation of chordoma into malignant fibrous histiocytoma.     

Recurrent aneurysmal fibrous histiocytoma

Aneurysmal fibrous histiocytoma is a rare variant of cutaneous fibrous histiocytoma that results from blood vessel proliferation and haemorrhage into a fibrous histiocytoma. The resulting lesion has a very different clinical appearance, hence the potential confusion with other skin lesions. This report describes the case of a 48 year old woman with a recurrent fibrous histiocytoma with prominent vasculature, which over a three year period recurred on two occasions, showing more progressive features of the aneurysmal variant. In addition, squamous lined cysts were present within this tumour, a finding that has not been described previously. The histological features of this rare lesion and the importance of the differential diagnosis from other similar appearing malignant lesions will be discussed.     

Palisading subcutaneous fibrous histiocytoma

A case of palisading subcutaneous fibrous histiocytoma, a very rare variant of fibrous histiocytoma (dermatofibroma), arising in the wrist of a 41-year-old man is presented. An unencapsulated subcutaneous tumor measuring 0.8 x 0.8 x 0.7 cm was histologically characterized by predominant nuclear palisading and a peripheral area with a pattern quite characteristic of conventional fibrous histiocytoma. Immunohistochemically, the tumor cells were strongly positive for vimentin, alpha-smooth muscle, and muscle actin, but negative for S-100 protein, indicating a fibroblastic or myofibroblastic nature. The patient has been well without recurrence for 6 years and 8 months after the excision. This neoplasm should be differentiated from benign and malignant skin or soft tissue tumors with a palisading pattern. Pathologists and clinicians should know of the existence of this type of fibrous histiocytoma and should avoid overdiagnosis and overtreatment.     

Progression of dermatofibrosarcoma protuberans to malignant fibrous histiocytoma: report of a case with implications for tumor histogenesis

A 79-year-old woman required amputation of her left leg for the control of a rapidly growing malignant fibrous histiocytoma. This tumor had developed at the precise site of repeated recurrence of a previously diagnosed dermatofibrosarcoma protuberans. Biopsy specimens from the recurrences revealed a gradual change in appearance from dermatofibrosarcoma protuberans to malignant fibrous histiocytoma.     

Primary malignant fibrous histiocytoma of the kidney

Primary renal malignant fibrous histiocytoma is a rare tumor of the kidney. It is clinically and radiologically indistinguishable from a renal cell carcinoma. Even following radical surgery, the tumor shows a strong predilection for local recurrence and the prognosis is generally poor. We report on a 32-year-old man with malignant fibrous histiocytoma of the kidney who remained free of recurrence for 1 year after radical nephrectomy.     

Reticular angiomatoid "malignant" fibrous histiocytoma--a case report with cytogenetics and molecular genetic analyses

Angiomatoid "malignant" fibrous histiocytoma is a rare sarcoma of low malignant potential that occurs most commonly in the extremities of children and young adults. Herein, we present a case of angiomatoid malignant fibrous histiocytoma with unusual histologic features arising in the mediastinum of an 80-year-old man. The tumor exhibited a reticular growth pattern and myxoid stroma. The tumor cells expressed epithelial membrane antigen and desmin. Cytogenetic analysis revealed the translocation t(2;22)(q33;q12). Molecular genetic analysis confirmed the rearrangement of the EWSR1 locus and the presence of the EWSR1/CREB1 fusion. This report expands the clinicopathologic spectrum of angiomatoid malignant fibrous histiocytoma and underscores the value of integrating morphologic, immunophenotypic, and molecular findings in the identification of its unusual morphologic variants.     

The rise and fall of malignant fibrous histiocytoma

The term malignant fibrous histiocytoma was coined by Stout and associates in the 1960s to encompass pleomorphic soft tissue sarcomas presumably derived from histiocytes that are capable of fibroblastic transformation. The concept was reaffirmed in the following 2 decades and malignant fibrous histiocytoma thus was regarded as the most common soft tissue tumor in older adults. However, recent more critical clinicopathologic, ultrastructural, and immunohistochemical studies have shown that malignant fibrous histiocytomas are not derived from histiocytic "facultative fibroblasts" and many neoplasms so diagnosed actually are pleomorphic subtypes of other sarcomas. Meticulous electron microscopic and immunohistochemical investigations also found that the more common storiform-pleomorphic, myxoid, and perhaps the giant cell subtypes are composed of variable mixtures of fibroblasts and phenotypically modulated fibroblastic cells, notably myofibroblasts and histiofibroblasts. On the basis of these findings, we propose a new classification for the above subtypes of so-called malignant fibrous histiocytoma, the majority of which are variants of pleomorphic fibrosarcoma.     

Malignant fibrous histiocytoma of bone.

Existence of an entity called malignant fibrous histiocytoma of bone was emphasized, based on two of our own cases experienced recently and on previous reports related to this tumor. Histologically the tumor resembles markedly the malignant fibrous histiocytoma originating in the soft part. In addition, an attempt was made to clarify its biological behavior, histological subclassification and criteria to be malignant and differential diagnoses from several other bone diseases which sometimes mimic this malignant bone tumor.     

Malignant fibrous histiocytomas and H-ras-1 oncogene point mutations.

AIMS: To investigate the types and the frequencies of H-ras-1 gene mutations in malignant fibrous histiocytomas. METHODS: Thirty five samples of malignant fibrous histiocytoma tissue were searched for point mutations within "hot spot" codons 12 and 13 of the H-ras-1 oncogene by the specific "nested" polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) and a direct cycle sequencing procedure. RESULTS: In contrast to previous reports, none of the tumours contained a point mutation or any other changes within or around the hot spot gene sequences. CONCLUSIONS: These data indicate that H-ras-1 oncogenic activation is not required in the molecular pathway of malignant fibrous histiocytoma formation and cannot be used as a discriminating factor for diagnostic sarcoma typing.