Pseudoanaplastic chondromyxoid fibroma

Chondromyxoid Fibroma of Distal Phalanx of the Great Toe: A Rare Clinical Entity

Chondromyxoid fibroma is a rare benign tumor of cartilaginous origin with myxoid and fibrous components. It accounts for approximately 1% of bone tumors. Metaphysis of long bones is the most common location of this tumor. However, there a few case reports of this tumor arising from epiphysis of short tubular bones of the hand and feet.

An 11-year-old girl presented to our OPD with complaints of pain and a gradually progressive swelling of the right great toe. On examination, the swelling was diffuse with no signs of inflammation. X-ray examination revealed a well-defined, longitudinally oval lytic lesion in the right distal phalanx of great toe, involving the growth plate and, eroding the medial cortex. Computed tomography (CT) scan did not show any evidence of calcification, septations or involvement of soft tissue. Open biopsy and curettage was done and the specimen was sent for histopathological examination. Histopathological examination (HPE) showed a lobular pattern consisting of myxomatous stroma and immature cartilaginous cells in lacunae. The lobules were separated by fibrous septae. It was reported to be Chondromyxoid fibroma. The patient presented six months later with persisting pain and X-ray showed recurrence of the tumor. Hence, complete excision of the tumor was done and the defect was filled using synthetic bone graft. At six months follow up, the patient did not complain of pain and X-rays showed signs of bone formation with incorporation of the graft.

Chondromyxoid fibroma is a low grade tumor, which may demonstrate nuclear atypia histologically and mimic chondrosarcoma. Differentiating these two is of paramount importance to avoid over-diagnosis and aggressive treatment. Recurrence is common with marginal excision and especially in younger patients like in our case. Complete resection is the mainstay of management. Long-term follow up of patients is necessary to watch for malignant transformation, a rare complication. Chondromyxoid fibroma is an extremely rare neoplasm of bone. There are no specific radiologic features, and histopathology provides a definitive diagnosis. It should be considered in differential diagnosis of lytic lesion, and differentiated from other tumors, especially from chondrosarcoma to treat the patient appropriately.

Dystrophy of the Great Toenail by Subungual Exostosis and Hyperostosis: Three Case Reports with Different Clinical Presentations

Subungual exostoses and hyperostoses of the great toenail are a differential diagnosis of nail tumors. We present 3 cases of subungual exostosis/hyperostosis with secondary nail dystrophy: a 36- and a 37-year-old woman as well as an 8-year-old boy. Two of the 3 patients suffered from pain. The 2 female patients presented with the classic dorsolateral firm protrusion, while the child presented with bilateral nail dystrophy with lateral wall hypertrophy. In this later case, a bony ridge was identified, which is an unusual subungual, nonprotruding type of exostosis. The hypertrophic lateral walls were removed by the Vandenbos technique. In the 2 former cases, complete excision of the bony lesions was performed with a proximal block. Healing by second intention was uneventful.

Chondromyxoid fibroma of the distal phalanx of the big toe

Chondromyxoid fibroma rarely arises in the distal phalanx of the toe. It shows a wide spectrum of histology, mimicking other primary bone tumors. A 40-year-old woman had persistent swelling of her big toe after a minor injury a few years ago before a consultation. A radiographic and magnetic resonance imaging study suggested a highly aggressive tumor. Amputation was performed, and pathology of the lesion showed chondromyxoid fibroma.

Fibrous dysplasia with degenerative atypia: a benign lesion potentially mistaken for sarcoma

Fibrous dysplasia is a benign disorder of bone in which proliferating fibrous tissue replaces the bony spongiosa. Cytologic atypia is generally not considered a feature of this proliferating tissue. We present a case of fibrous dysplasia with marked atypical nuclear changes consistent with degenerative or regressive changes. A 42-year-old man presented with an osteolytic lesion of the right iliac bone. Histologic study demonstrated a fibro-osseous lesion with woven bone trabeculae and bland-looking fibrous tissue. Several areas showed atypical cells with enlarged pleomorphic nuclei and bizarre features. There was no change in the nuclear-cytoplasmic ratio nor were mitotic figures identified. The differential diagnosis is discussed. When radiographic and other histologic findings suggest fibrous dysplasia, the atypical nuclear changes should not, by themselves, alter the diagnosis.

Pseudoanaplastic tumors of bone

OBJECTIVE

To discuss the concept of pseudoanaplastic tumors of bone, which pathologically show hyperchromatism and marked pleomorphism with quite enlarged, pleomorphic nuclei, but with no to extremely rare, typical mitoses, and to propose guidelines for their diagnosis.

DESIGN AND PATIENTS

From a database of 4,262 bone tumors covering from 1971 to 2001, 15 cases of pseudoanaplastic bone tumors (0.35% of total) were retrieved for clinical, radiographic and pathologic review. Postoperative follow-up after surgical treatment was at least 3 years and a maximum of 7 years.

RESULTS

There were eight male and seven female patients. Their ages ranged from 10 to 64 years with average of 29.7 years. Pathologic diagnoses of pseudoanaplastic variants of benign bone tumors included: osteoblastoma (4 cases), giant cell tumor (4 cases), chondromyxoid fibroma (3 cases), fibrous dysplasia (2 cases), fibrous cortical defect (1 case) and aneurysmal bone cyst (1 case). Radiography of all cases showed features of a benign bone lesion. Six cases, one case each of osteoblastoma, fibrous dysplasia, aneurysmal bone cyst, chondromyxoid fibroma, giant cell tumor and osteoblastoma, were initially misdiagnosed as osteosarcoma. The remaining cases were referred for a second opinion to rule out sarcoma.

CONCLUSIONS

Despite the presence of significant cytologic aberrations, none of our cases showed malignant behavior following simple curettage or removal of bony lesions. Our observation justifies the concept of pseudoanaplasia in some benign bone tumors as in benign soft tissue tumors, especially in their late evolutionary stage when bizarre cytologic alterations strongly mimic a sarcoma.