Malignant fibrous histiocytoma of bone associated with type-1 neurofibromatosis. A case report

Pleomorphic Sarcoma in a Patient with Osteopetrosis

Osteopetrosis comprises a rare, heterogeneous group of heritable conditions that are characterized by a defect in bone resorption by osteoclasts. We report the case of a 53-year-old woman with previously undiagnosed osteopetrosis who presented with a pathologic proximal humeral fracture secondary to pleomorphic sarcoma, which is previously undescribed in the English literature. Management of the primary lesion necessitated ablative surgery, but the malignancy nonetheless was associated with rapidly progressive metastatic disease.

Neurofibromatosis type 1 and malignancy in childhood

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary neurocutaneous syndrome characterized by multi-system involvement and an increased incidence of both benign and malignant tumors. In this study, we evaluated the clinical presentation and prognosis of NF1 and malignancy. Between 1975 and 2013, 26 (5%) of the 473 patients with NF1 at our center developed non-neurofibroma neoplasms. The patient files of 26 subjects with tumors, other than optic glioma, were analyzed retrospectively to evaluate clinical features and treatment results. The age at diagnosis of NF1 ranged from 3 months to 16 years (median 5.5 years). The age range at tumor diagnosis was 1.5-33 years (median 8 years) in these 26 patients. The tumor histological subtypes included the following: 12 soft-tissue tumors (6 malignant peripheral nerve sheath tumors (MPNST), 5 rhabdomyosarcomas (RMS) and 1 malignant fibrous histiocytoma), 11 brain tumors (6 low-grade gliomas, 3 high-grade gliomas, and 2 medulloblastoma), 2 neuroblastomas and 1 non-Hodgkin's lymphoma. Twelve of 26 patients were alive at the time of the study. Although benign brain tumors with NF1 are more common, high-grade brain tumors also occur. Thus, careful and regular follow-up is crucial for early detection of malignancy in NF1 patients.

Imaging findings, prevalence and outcome of de novo and secondary malignant fibrous histiocytoma of bone

OBJECTIVE

To evaluate the radiographic and magnetic resonance (MR) imaging features of primary and secondary malignant fibrous histiocytoma in bone and determine the demographics, prevalence and outcome of patients with this tumor.

MATERIALS AND METHODS

A retrospective search of files from two institutions identified 28 patients with malignant fibrous histiocytoma (MFH) of bone. Microscope slides were reviewed to confirm diagnosis and identify any pre-existing lesions. Medical records were reviewed with respect to patients' demographic characteristics and outcomes.

RESULTS

Radiographic features demonstrated an aggressive osteolytic lesion with a permeative pattern of bone destruction. Periosteal reaction was seen in three of 13 lesions. T1-weighted images (T1WIs) demonstrated signal intensity iso- to slightly hyperintense to muscle. T2-weighted images (T2WIs) demonstrated mildly higher signal intensity than that of muscle. The 5-year survival rate was 53%. The tumor arose secondarily in pre-existing lesions in 43% of patients. Metastases occurred in 46% of patients during the course of the disease, with pulmonary and osseous metastases being the most common.

CONCLUSION

Secondary MFH of bone was slightly less common than primary MFH and had a prognosis similar to that of primary MFH of bone. MR imaging showed variable and somewhat unusual low to intermediate T2 signal characteristics for a radiographically malignant osteolytic lesion.

Diffuse-type tenosynovial giant cell tumor in association with neurofibromatosis type 1-Noonan syndrome: possibly more than a chance relationship

A case of diffuse-type tenosynovial giant cell tumor arising in the left upper extremity is reported in a 23-year-old man with neurofibromatosis type 1 (NF1)-Noonan syndrome. The predominately mononuclear cellular proliferation with psammomatous calcifications had the immunohistochemical and ultrastructural features of a fibrohistiocytic neoplasm. This uncommon type of soft tissue neoplasm occurring in this unique clinical setting served to open an inquiry into the subject of non-neurogenic tumors in association with NF1 and Noonan syndrome, both manifested in our patient. Nonossifying fibroma of bone as a presumptive fibrohistiocytic tumor is an uncommon but well-documented manifestation in NF1, whereas in Noonan-like syndrome, both giant cell granuloma and pigmented villonodular synovitis are recognized as associated lesions with histologic and immunophenotypic similarities with the diffuse-type tenosynovial giant cell tumor.