Chondromyxoid fibroma of the acromium with soft tissue extension

Chondromyxoid fibroma is an unusual, benign tumor of cartilaginous origin and represents less than 1% of all primary bone tumors. It usually involves the long bones around the knee joint or the flat bones of the pelvis or ribs. Soft tissue extension is also thought to be rare in these lesions. They are usually eccentrically located in the metaphyses of the long bones and centrally in the flat bones. The radiographic appearances are characteristically those of a single, lytic lesion with lobulated margins, septations, cortical expansion and a sclerotic rim. Histologically, they display a lobulated pattern with spindle-shaped cells lying within a myxoid matrix with areas of hyaline cartilage. The differential diagnosis includes giant cell tumor, chondroblastoma or enchondroma as well as chondrosarcoma. The rarity of these lesions may render the diagnosis difficult to make, especially when the lesion involves an unusual site such as the acromium. Received: 21 June 1999 Revision requested: 27 September 1999 Revision received: 27 October 1999 Accepted: 28 October 1999     

Cystic fibrous dysplasia mimicking giant cell tumor: MRI appearance

We report the case of a 43-year-old man who presented with an osteolytic and expansive lesion in the left distal femur mimicking a giant cell tumor. Magnetic resonance imaging (MRI) showed that most of the lesion was cystic, and histological examination revealed fibrous dysplasia with marked cystic degeneration. Radiographic findings of cystic fibrous dysplasia in the end of a long bone may be similar to those of a giant cell tumor, and a biopsy is essential for the final diagnosis. Received: 4 June 1999 Revision requested: 10 August 1999 Revision received: 13 September 1999 Accepted: 15 September 1999     

Metadiaphyseal chondroblastoma of the thumb

Chondroblastoma is typically located in the epiphysis. Predominant metadiaphyseal location is very rare, as is involvement of the digits. We describe a case of chondroblastoma involving the metadiaphysis of the thumb. The patient was a 13-year-old boy who presented with pain and swelling of his left thumb. Radiographs showed an expanded lytic lesion involving the whole metaphysis and diaphysis of the proximal phalanx, which subsequently progressed to involve the epiphysis. Curettage and bone grafting were done. Received: 9 July 1999 Revision requested: 12 August 1999 Revision received: 1 November 1999 Accepted: 4 November 1999     

Hyperfunctioning parathyroid carcinoma

Primary hyperparathyroidism is rarely caused by carcinoma. We report a patient who manifested many of the clinical and radiographic features of the disease. When encountering symptomatic hypercalcemia with or without a palpable neck mass, carcinoma should be considered in the differential diagnosis. Patient survival depends on an aggressive surgical approach to the primary lesion and recurrent disease. Received: 27 May 1999 Revision requested: 28 June 1999 Revision received: 22 September 1999 Accepted: 27 September 1999     

De novo malignant transformation of giant cell tumor of bone

Two cases of malignant lesions are reported, both of which arose secondary to an originally benign giant cell tumor (GCT) of bone. The first case was a typical benign GCT, which occurred in the left proximal tibia of a 31-year-old woman. The tumor was treated by curettage and bone grafting. However, it recurred twice during 15 years of follow-up. The second recurrence showed that the lesion histologically had turned into malignant fibrous histiocytoma. The second case also started as an initially benign GCT that arose in the left distal femur of a 41-year-old man. The patient underwent curettage and bone grafting. The lesion recurred 13 years postoperatively. The histological appearance of the recurrent tumor showed it to be an osteogenic sarcoma. In both patients, radiation had never been given. Malignant transformation has rarely been reported in patients with GCT of bone who have not received radiation treatment. Received: 12 June 2000 Revision requested: 17 August 2000 Revision received: 13 October 2000 Accepted: 18 October 2000     

Neurilemmoma of the mandible

Intraosseous neurilemmoma is rare, representing less than 1% of benign primary bone tumors. The site most commonly involved is the mandible. We report on a neurilemmoma of the mandible in a 30-year-old woman. A panoramic radiograph of the mandible showed a well-defined unilocular osteolytic lesion with a thin uniform sclerotic margin located in the body of the mandible. The CT scan confirmed a well-defined osteolytic lesion with thinning of the cortex of the body of the left side of the mandible. Histologically, the lesion was a moderately cellular neoplasm with distinct palisading and numerous Verocay bodies. Ultrastructurally, the cytoplasmic membranes were distinct and coated by amorphous bands of basal lamina. Complete excision was achieved by removing the tumor from the inferior alveolar nerve. Received: 26 February 1999 Revision requested: 29 March 1999 Revision received: 12 April 1999 Accepted: 13 April 1999     

MRI appearance of clear cell hidradenoma

We present the first reported MR imaging findings of a histologically proven clear cell hidradenoma. A fluid level was noted on all pulse sequences in this lesion, which demonstrated a prominent hemorrhagic component on sectioning. The presence of an enhancing nodule was also noted, differentiating this lesion from a post-traumatic hematoma. Fluid levels in a well-defined subcutaneous soft tissue mass should suggest the possibility of a hidradenoma. Received: 19 June 1998; Revision requested: 29 July 1998; Revision received: 28 October 1998; Accepted: 29 October 1998     

Intramuscular metastasis from malignant melanoma: MR findings

We present a rare case of intramuscular metastasis from malignant melanoma. The lesion showed intermediate to high signal intensity on T1-weighted magnetic resonance (MR) images and mixed signal intensities containing high and low signals on T2-weighted images. The signal intensity on T1-weighted images, which is due to the paramagnetic effect of melanin, is a characteristic MR finding of this entity. Received: 10 June 1999 Revision requested: 7 July 1999 Revision received: 9 August 1999 Accepted: 9 August 1999     

Extraosseous calcified plasmacytoma causing thoracic myelopathy

We report on a rare, calcified, plasma cell tumor of the spine causing progressive myelopathy. Other unusual features were the lack of an osseous lesion at the site of the mass, considerable calcified amyloid within the mass but no identifiable amyloid elsewhere, and normal serum immunoelectrophoresis. Received: 12 February 1999 Revision requested: 18 March 1999 Revision received: 19 April 1999 Accepted: 20 April 1999     

Popliteal vascular malformation simulating a soft tissue sarcoma

Differentiation of vascular abnormalities from soft tissue sarcomas may be difficult on clinical grounds, but is usually possible on imaging criteria. We report the MRI and digital subtraction angiography (DSA) findings in a patient presenting with a mass behind the knee. We discuss differentiating features and review the literature of similar cases. Received: 28 January 1999 Revision requested: 23 February 1999 Revision received: 29 March 1999 Accepted: 30 March 1999     

Non-epiphyseal chondroblastoma arising in the iliac bone, and complicated by an aneurysmal bone cyst: a case report and review of the literature

Chondroblastoma is a benign bone tumor that typically arises in the epiphysis of a long bone. However, when it occurs in non-epiphyseal location in flat bones, it may create a diagnostic problem. We describe such a case of chondroblastoma arising in the iliac bone. A 29-year-old man was incidentally found to have a bony pelvic lesion while undergoing evaluation for Crohn’s disease. The radiographs and CT revealed an expansile lytic lesion in the right iliac bone. A core biopsy of the lesion was performed. The histopathology revealed the lesion to be a chondroblastoma with secondary features of aneurysmal bone cyst. An en bloc surgical resection of the tumor was performed.     

Multifocal osteosarcoma as second tumor after childhood retinoblastoma

We present a case of multifocal osteosarcoma (MFOS) arising 11.5 years after successful treatment of bilateral retinoblastoma. The clinical, imaging and pathological findings at onset, after therapy, and during follow-up are described. Fluorescent in situ hybridization did not reveal a deletion of the RB-1 retinoblastoma gene, although the presence of an inactivating mutation invisible to this method cannot be ruled out. The MFOS may have been a second multifocal tumor associated with the original retinoblastoma or a post-irradiation sarcoma with extensive metastases. Received: 20 November 1998 Revision requested: 5 January 1999 Revision received: 8 March 1999 Accepted: 19 March 1999     

Pigmented villonodular synovitis of the hip presenting as a retroperitoneal mass

We present an unusual case of diffuse pigmented villonodular synovitis (PVNS) of the hip presenting as a large retroperitoneal mass in an asymptomatic 39-year-old man. Initial imaging characteristics and findings on core needle biopsy suggested soft tissue sarcoma. However, incisional biopsy showed findings of PVNS. The patient underwent radical synovectomy and total joint replacement, with no change in the large retroperitoneal component after 15 months of follow-up. Received: 15 June 2000 Revision requested: 8 September 2000 Revision received: 14 March 2001 Accepted: 15 March 2001     

Osteoblastoma-like osteosarcoma

We report an osteoblastoma-like osteosarcoma in the right proximal fibula in a 22-year-old woman. Radiographs showed an irregular osteolytic lesion from the metaphysis to the epiphysis in the proximal fibula with partial destruction of cortical bone. Tissue from a biopsy indicated a typical osteoblastoma. Curettage and bone graft was performed. One year after the surgery, local recurrence occurred, and a wide excision was performed. Histological examination of the en-bloc surgical specimen revealed the tumor had permeated through the host bony trabeculae, although the nuclear atypia was not marked. Immunohistochemical expression of MIB-1 was detected in 9.0% of cells. Received: 22 May 2000 Revision requested: 23 June 2000 Revision received: 10 July 2000 Accepted: 13 July 2000     

Glomus tumor of the trachea

We report a case of a glomus tumor in the trachea which was an incidental finding in a 66-year-old man. The histological picture and immunohistochemical profile were typical for this tumor. The glomus tumor is an exceedingly rare mass lesion in the trachea, but it is useful to keep it among differential diagnostic alternatives when a tracheal tumor is seen on radiographs or endoscopy. Received 26 May 1997; Revision received 29 July 1997; Accepted 1 August 1997     

Epithelioid hemangioma of bone

Epithelioid hemangioma of bone is a rare type of angiomatous tumor. We report a documented case of epithelioid hemangioma occurring in the distal femur of a 35-year-old man. The clinical, radiographic, MR imaging and histologic findings of the tumor are described. Radiographs showed a well-defined expanding, osteolytic lesion in the diaphysis of the femur. MR imaging showed the lesion to have low signal intensity on T1-weighted images and intermediate signal intensity on T2-weighted images. Grossly the lesion was multiloculated with a dark brown, jelly-like content. To characterize the imaging appearances of epithelioid hemangioma, we reviewed the available literature on the subject. Received: 14 February 2000 Revision requested: 28 March 2000 Revision received: 31 May 2000 Accepted: 1 June 2000     

Synchronous Paget’s sarcoma of tibiae in which Paget’s disease was limited to these bones

A 51-year-old native of Rio de Janeiro presented with bilateral synchronous Paget’s sarcomas in the tibiae, which developed in the upper right tibia and in the distal third of the left tibia. There were no other areas of Paget’s disease. The largest tumor spread to the right inguinal nodes and also soft tissue. The tumor in the left tibia spread dramatically in the soft tissues up the leg and only involved the medullary cavity in its inferior portion. The patient died, but there was no autopsy. Comments are made about the prevalence of Paget’s disease in Rio de Janeiro. Received: 8 April 1999 Revision requested: 10 May 1999 Revision received: 23 June 1999 Accepted: 1 July 1999     

Vertebral intra-osseous chordoma or giant notochordal rest?

Chordomas of the lumbar vertebral bodies are rare. We report an unusual case of an entirely intra-osseous chordoma of the fifth lumbar vertebra treated by vertebrectomy. Conventional radiographs and scintigraphy were normal. The lesion was well visualised by MR imaging, but showed only slight sclerosis on CT. We give our reasons for making a diagnosis of chordoma rather than giant notochordal rest and discuss the problems of management resulting from this diagnostic dilemma. Received: 25 February 1999 Revision requested: 2 March 1999 Revision received: 15 March 1999 Accepted: 18 March 1999     

Sclerotic bone metastases from sarcomatoid renal cell carcinoma

We present a case of sarcomatoid renal cell carcinoma with multiple sclerotic skeletal metastatic lesions. Renal cell carcinoma is frequently metastatic at presentation, with a high incidence of skeletal involvement, classically described as osteolytic. However, sclerotic or osteoblastic metastatic skeletal lesions from renal cell carcinoma are rare, with only two previous reports identified in the literature, neither of which involved the sarcomatoid variant of renal cell carcinoma. In our case the sclerotic metastases were characterized by bone scan, computed tomography (CT), magnetic resonance imaging (MRI), and histologic analysis. Received: 8 April 1999 Revision requested: 27 May 1999 Revision received: 24 June 1999 Accepted: 29 June 1999     

Extraskeletal myxoid chondrosarcoma of the knee

Extraskeletal myxoid chondrosarcoma is an uncommon neoplasm, accounting for less than 2% of all soft tissue sarcomas. It affects adult males with a median age in the fifth decade at the time of diagnosis. The tumor usually arises in the deep soft tissues, especially in the lower extremities. Patients present with a gradually enlarging mass that may or may not be associated with pain. This report describes a 25-year-old man who initially presented with a 4- to 5-year history of right knee pain and an enlarging mass in the right knee. Evaluation revealed a cartilaginous neoplasm with no evidence of metastatic disease. The tumor was widely excised and an allograft reconstruction was performed. The patient was closely followed with an eventual above the knee amputation for recurrent myxoid chondrosarcoma. At 34 months, retroperitoneal metastases were noted on abdominal CT. The patient underwent a left radical nephrectomy, renal vein thrombectomy and enucleation of the mass in the right kidney, distal pancreatectomy, and splenectomy. The patient received postoperative chemotherapy. Forty-eight months after initial diagnosis, the patient was found to have recurrent abdominal and retroperitoneal lesions. At 64 months, the patient died from complications of extraskeletal myxoid chondrosarcoma. Received: 6 July 1998 Revision requested: 7 August 1998 Revision received: 29 January 1999 Accepted: 3 February 1999