Can an exostosis be free floating without any continuity to the underlying bone: A diagnostic dilemma

Abstract

A forty year old female presented with swelling on medial aspect of left thigh since four years. Radiographs showed a large mass at the inferior surface of the left femoral neck. CT scan revealed a well defined lobulated mass lesion involving muscles of adductor compartment of thigh. MRI showed lobulated periarticular, intramuscular, non enhancing lesion isointense to the bone, but without any continuity to the adjacent femur. Histopathology of the excised lesion turned out to be osteochondroma with origin from soft tissue. This case highlights an important differential diagnosis to be considered whenever an ossified mass is located in soft tissue.

About a misleading calcified mass of the elbow: Soft tissue osteochondroma: A case report

“…Synovium had also been postulated as a possible origin. Kanwat et al [2] think that a non-union of a fracture of a pedunculated osteochondroma can result in a soft tissue osteochondroma.…”

“…Osteochondromas are one of the most common bone tumours, making up 10–15% of all bone tumours and 20–50% of benign bone tumours [1] . It is a bone exostosis in which a continuous cortical layer projects from the underlying bone [2] . Approximately 50% occur in the long bones of the lower extremity, especially around the knee, in the distal femur, and proximal tibia.…”

When a Pilar Cyst Is Not a Pilar Cyst: Answer

“…In the dermis and superficial subcutis, the differential diagnosis could include ossifying pilomatricoma, osteoma cutis, miliary osteoma, and subepidermal calcified nodule. 12,13 Evidence of pilomatrical differentiation may be sparse in ossifying pilomatricoma, but pathognomonic ghost cells are usually at least focally discernible (Figure 1A and B). Cutaneous ossification is another relatively common phenomenon, sometimes accompanying cutaneous calcinosis, and can be further classified as metaplastic ossification in the setting of inflammation, trauma, and neoplasia or as idiopathic osteoma cutis (Figure 1C).…”

Solitary submandibular soft tissue osteochondroma: A rare case report

“…Among all benign soft-tissue tumors, cases of extraskeletal osteochondroma account for an estimated 1.5% [ 7 ]. Lesions to be considered as a differential diagnosis in well-circumscribed bony masses confined within the soft tissue of the oral and maxillofacial skeleton include tumoral calcinosis, lipomatous lesion, myositis ossificans, extraskeletal osteosarcoma, and synovial sarcoma [ 3 , [8] , [9] , [10] , [11] , [12] ].…”