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Volume 82, June 2026, 152618
Author links open overlay panelRadhika Jayan a, Bharat Rekhi a b, Mukta Ramadwar a b, Poonam Panjwani a bShow moreHighlights•This constitutes an updated series of OFDs and adamantinomas from our subcontinent.
•OFD and adamantinoma are associated diagnostic errors, given overlapping features.
•OFD is conservatively managed, while all adamantinomas requires complete resection.
•We did not observe progression in any OFD to adamantinoma during a limited follow-up.
•OFD and adamantinoma should be differentiated from their mimics.
AbstractOsteofibrous dysplasia (OFD) and adamantinoma are rare primary bone tumors. The present study is a clinico-pathological analysis of OFDs and adamantinomas, highlighting the value of distinguishing these tumors from their mimics and evaluating their proximity. OFDs, adamantinomas, fibrous dysplasias (FDs), and intraosseous synovial sarcomas (SS) of the tibia and fibula, diagnosed from 2012 to 2024 (12 years) were retrieved. Fifty-eight tumors were reviewed, and finally, 19 OFDs and 28 adamantinomas were analyzed. After a review, the diagnosis was modified in 12/58 (20.7%) tumors; with 4 OFDs revised to FDs; 2 FDs to OFDs; 2 intra-osseous SSs to classic adamantinomas; 3 OFD-like adamantinomas to classic adamantinomas, and a single de-differentiated adamantinoma to classic adamantinoma. The median age for OFD (10 years) was lower than that of adamantinoma (25 years). The radiological impression concurred with the histopathological diagnosis in 40% of OFDs and 60% of adamantinomas. Among 28 adamantinomas, there was a single OFD-like adamantinoma, 25 classic adamantinomas, and 2 dedifferentiated adamantinomas. Pan keratin (AE1/AE3) was positive in 18/19 (94.7%) OFDs and 19/20 (95%) adamantinomas. P40 (5/5, 100%) and p63 (6/8, 75%) were useful in the diagnosis of adamantinoma. Most adamantinomas were treated with surgery. None of the OFDs progressed to an adamantinoma during a median follow-up of 51.15 months(range = 4.36 to 97.94 months). Five out of 28 (17.9%) patients with an adamantinoma developed recurrences and 5 (17.9) developed metastases. The most commonly associated patterns with recurrences and metastasis in a classic adamantinoma were spindle and basaloid. The present study constitutes the first and the largest series of OFDs and adamantinomas from our subcontinent. OFD, OFD-like adamantinoma and adamantinoma may display overlapping clinico-radio-pathological profiles, and as such are potentially associated with diagnostic errors. Although there is a morphological continuum between OFD and adamantinoma, we did not observe a disease progression during the limited follow-up. It is crucial to distinguish an OFD and an adamantinoma from their various mimics, given treatment-associated implications. A long-term follow-up is suggested, as recurrences and metastases can occur late during the disease course.
IntroductionOsteofibrous dysplasia (OFD) and adamantinoma constitute rare bone tumors, accounting for 0.2% and 0.4% of all primary bone tumors [1], [2]. OFD is a benign fibro-osseous tumor of the long bones that arises in the anterior cortex of the tibia and/or fibula during childhood, histopathologically comprises trabeculae of woven bone with osteoblastic rimming, with the intervening fibrous component containing bland spindle cells. Immunohistochemically, the scattered cells show keratin positivity, which constitutes a significant diagnostic feature. Adamantinoma of long bones is a biphasic tumor characterized by various morphological patterns, comprising an epithelial component within a bland osteofibrous component. The subtypes of adamantinoma include: OFD-like adamantinoma, classic adamantinoma, and a de-differentiated adamantinoma. There has been a large, multi centre study on OFD-like and classic adamantinomas in the western population [3]. However, there is no substantial or comprehensive study from our subcontinent regarding the clinicopathological features of these rare tumors, especially in terms with the recent updates and the ultra-rare subtypes. The present study is a detailed clinicopathological analysis of OFDs, various subtypes of adamantinomas, and an attempt to evaluate the proximity between these two tumors.
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Access through your organizationSection snippetsMaterials and methodsThis was a retrospective study approved by the Institutional Ethics Committee (IEC). The study included the evaluation of histopathological sections along with clinico-radiological details of patients from 2012 to 2024 (12 years). Cases before 2012 were excluded due to the unavailability of slides and blocks. Cases of OFD and adamantinoma diagnosed from 2012 to 2024 were retrieved from the institutional search engine. Cases diagnosed as “intra-osseous synovial sarcoma” and “fibrous dysplasia
ResultsA revision of diagnosis was made in 12/58 (20.7%) tumors. Four OFDs were revised to FDs based on lack of both, osteoblastic rimming, as well as singly scattered keratin-positive cells. Two FDs were revised to OFDs, given areas showing woven bone with osteoblastic rimming and scattered keratin-positive cells. Two intra-osseous synovial sarcomas were revised to classic adamantinomas, including one that was negative for SS18::SSX fusion by RT-PCR. Three tumors previously classified as OFD-like
DiscussionThe present study describes the clinicopathological features, including histopathological spectrum, associated diagnostic challenges, treatment details, and outcomes of 19 OFDs and 28 adamantinomas, according to the current 5th edition WHO classification. This also highlights the value of differentiating these tumors from their mimics, which can present a diagnostic dilemma and have significant treatment-related implications.
The median age of the patients harboring an OFD was 10 years in the
CRediT authorship contribution statementRadhika Jayan: Writing – original draft, Resources, Methodology, Formal analysis, Data curation. Bharat Rekhi: Writing – review & editing, Writing – original draft, Supervision, Resources, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. Mukta Ramadwar: Writing – review & editing, Resources, Methodology, Investigation. Poonam Panjwani: Writing – review & editing, Methodology, Investigation.
Source of fundingNone.
Declaration of competing interestNone.
AcknowledgementsThe first two authors have equally contributed to the study and the manuscript.
We would like to thank all the colleagues of the bone and soft tissue disease management group and the colleagues from the division of molecular pathology and traslational medicine, Tata Memorial Hospital, Mumbai.
The study was presented as a platform presentation during the 37th European Congress of Pathology (ECP), 6th–10th September 2025, Vienna, Austria.
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