Epiphyseal osteosarcoma revisited: four illustrative cases with unusual histopathology and literature review

Abstract

Osteosarcomas arising in the epiphysis are extremely rare and easily missed in the diagnostic consideration of epiphyseal tumors. It is the purpose of this study to delineate the clinical pathological characteristics of 'epiphyseal osteosarcoma' under the definition of 'a solitary long bone osteosarcoma radiographically considered an epiphyseal tumor for which the main radiologic differential diagnosis would encompass giant cell tumor, chondroblastoma and clear cell chondrosarcoma'. Four such cases with unusual histopathology were retrieved among 110 cases of osteosarcoma. Their clinical, radiological and pathological features, together with all 10 reported cases, were analyzed. The radiographic diagnoses of our four cases include two giant cell tumors, one chondroblastoma and one clear cell chondrosarcoma but turn out to be fibroblastic, giant cell rich, telangiectatic and epithelioid variant of epiphyseal osteosarcoma. Including our patients, the 14 reported epiphyseal osteosarcomas comprise 8 males and 6 females, the age at presentation ranges from 11 to 39 years, two-third in the second decade, 71.4% affect the femur. Due to their epiphyseal locations, many carry benign radiological diagnoses notably giant cell tumor and chondroblastoma. Epiphyseal osteosarcomas may not only masquerade as benign radiological bony lesions but also assume many histological patterns; orthopedic surgeons, radiologists and pathologists should be aware of such possibility. Their behavior and prognosis are dictated by the histologic types, grading and staging rather than location.

Giant cell‐rich osteosarcoma: A match pair analysis of 11 new cases and literature review of 56 patients

“…A GCRO was defined as a primary bone tumor with malignant cells producing lace-like primitive bone matrix coexisting with nonneoplastic osteoclast-type giant cells scattered through the entirety of the tumor. [10][11][12] Using these criteria, 11 patients (six males) at a mean age of 43 years (range, 15-83 years), diagnosed with GCRO between 1993 and 2012, were included (Table 1). The mean followup was 14 years (range, 5 days to 29 years).…”

“…After obtaining ethical approval, a registry‐based search was used to identify all patients treated for GCRO between 1990 and 2020 at three metropolitan, tertiary‐care university‐based cancer centers. A GCRO was defined as a primary bone tumor with malignant cells producing lace‐like primitive bone matrix coexisting with non‐neoplastic osteoclast‐type giant cells scattered through the entirety of the tumor 10–12 . Using these criteria, 11 patients (six males) at a mean age of 43 years (range, 15–83 years), diagnosed with GCRO between 1993 and 2012, were included (Table 1).…”

“…Although a number of case reports have been published over the last decades, no study has reported outcomes of more than 10 patients. Moreover, the limited case series of four to nine patients did not include any comparison groups, limiting knowledge of baseline demographics and survival among GCRO 10–12 . This limitation is even more critical as nationwide databases such as the Surveillance, Epidemiology, and End Results program do not differentiate for GCRO 3 …”

Kinesin superfamily proteins: roles in osteosarcoma

“…Osteosarcoma is one of the most common primary malignant bone tumors, with a 5-year survival of 70% to 80% [1]. It usually occurs in adolescents aged between 10 and 25, and its prevalence is slightly higher in men than in women [2]. Osteosarcoma is a rare disease but is still considered the third most common cancer owing to its high metastasis and mortality rates [3,4].…”

Fibular giant cell-rich osteosarcoma virtually indistinguishable radiographically and histopathologically from giant cell tumor-analysis of subtle differentiating features

“…Giant cell‐rich osteosarcoma, first described by Bathurst in 1986, is characterized by the striking features of an abundance of osteoclastic giant cells on the one hand and paucity of tumor osteoid on the other , resulting in its easy confusion with giant cell tumor during biopsy interpretation, especially in occasional cases that the giant cell‐rich osteosarcoma assumes an epiphyseal location .…”