Osteofibrous dysplasia-like adamantinoma versus osteofibrous dysplasia in children: A case report of challenging diagnosis

Recurrent Adamantinoma With Fibrous Dysplasia-like Feature

Adamantinoma (AD) is a rare, slow-growing primary malignant bone tumor characterized by a biphasic morphology of clusters of epithelial cells and spindle cell osteofibrous components. A strong relationship between AD and osteofibrous dysplasia (OFD) has been proposed, while fibrous dysplasia (FD) has been rarely associated with AD. We present an AD case that was followed and histologically evaluated 3 times over 6 years with different morphological patterns. The tumor in the primary biopsy and after complete resection showed classical features of AD and osteofibrous-like pattern, while the recurrent lesion presented with exclusively spindle cell morphology and was thus diagnosed as FD. However, the extensive immunohistochemical analysis in all 3 lesions revealed strong reactivity for pancytokeratin, vimentin, p63, and podoplanin, which are characteristic for AD. Although, in the FD-like section of the tumor from the first recurrence the positivity of podoplanin was stronger than pancitokeratin, which was variably positive on spindle cells. The present case highlights the problem of diagnosing AD based on a single biopsy with one tumor's component predominating over the other, and at the same time emphasizes the importance of using immunohistochemical staining for keratin and podoplanin when the histopathological features of (osteo)fibrous lesion can be linked to AD.

Osteofibrous dysplasia-like adamantinoma: A case report and literature review

ABSTRACT BACKGROUND

Osteofibrous dysplasia-like adamantinoma (OFD-like adamantinoma), classical adamantinoma and dedifferentiated adamantinoma were previously considered to be three subtypes of adamantinoma of long bones. In the 5th edition of the World Health Organization (WHO) classification of bone tumors in 2020, OFD-like adamantinoma was newly proposed and classified as an intermediate-locally aggressive tumor in other mesenchymal tumors of bone. OFD-like adamantinoma is rare, accounting for only 0.4% of all primary bone tumors. OFD-like adamantinoma is often misdiagnosed due to the insufficient understanding of it. Here we report a case of OFD-like adamantinoma treated in our hospital with a literature review.

CASE PRESENTATION

The patient, a 14-year-old male, had swelling in his right leg with intermittent pain for one year. Plain radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed. Based on the radiological and histological examinations, a diagnosis of OFD-like adamantinoma was suspected. After admission, the patient underwent tumor resection of the right tibia, free transplantation of the left fibula and internal fixation. After resection of the tumor, the wound recovered well, the vital signs were stable, and activity was normal. The patient has been followed up for more than a year with no recurrence or distant metastasis.

CONCLUSION

OFD-like adamantinoma is a rare primary bone tumor with nonspecific clinical features. Imaging examination can demonstrate the lesion and help diagnosis. The pathological discovery of epithelioid tissue is the key evidence for diagnosis.

A 15 year-old-girl with persistent leg pain diagnosed as a giant cell tumor of the tibial diaphysis: A case report and review of the literature

Introduction

Giant cell tumor (GCT) is a benign bone tumor typically seen in epiphysis or metaphysis of mature long bones. Multiple large multinucleated giant cells dispersed among mononuclear spindle cells and monocytes constitute characteristic histological background of GCT of bone (GCTB).

Case presentation

A 15-year-old girl was admitted to our hospital with the complaint of pain and swelling in the left leg with difficulty in walking for 2 years. On X-ray of the left leg, osteolytic, expansile, eccentric lesion with sclerotic bone margin on the diaphysis of the tibia was seen suggesting oesteofibrous dysplasia. MRI demonstrated findings compatible with adamantinoma. The subsequent histology report was rather surprising, consistent with giant cell tumor of the bone. Extended intralesional curettage was done with the help of a high-speed burr followed by chemical cauterization and bone grafting. The patient was followed up for 2 years. The patient could walk normally without assistance or any signs of a recurrence.

Discussion

GCTB commonly affects people in their third and fourth decades of life and involves epiphysis of the long bone, but this is a case of diaphyseal GCT, at an age of 15 years. It is challenging to diagnose GCT, if present in an unusual location, unless confirmed by histopathological examinations.

Conclusion

A multi-disciplinary approach is required to correctly reach the diagnosis of GCT when it happens to be in an uncommon location(s). Early diagnosis with appropriate treatment and long-term follow-up is mandatory for the successful outcome of the treatment.

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GCTB commonly affects people in their third and fourth decades of life and involves epiphysis of the long bone.

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We report an unusual case of a 15-year-old girl diagnosed as a giant cell tumor in the diaphysis of the tibia.

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Early diagnosis, appropriate treatment, and long-term follow-up are essential for a successful treatment outcome.

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Extended intralesional curettage was performed with the help of a high-speed burr followed by chemical cauterization and bone grafting.

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After surgery and close monitoring at regular intervals for 2 years, the patient was able to walk normally without any signs of recurrence.

Osteofibrous dysplasia-like adamantinoma of isolated fibula in a child mimicking chronic osteomyelitis with pathological fracture

The occurrence of a pathological fracture in children requires a rigorous diagnostic approach in order to establish the etiology and to develop a precise therapeutic strategy. Several causes are associated with these fractures, the most frequent being benign tumors in children in developed countries and chronic osteomyelitis in developing countries. More rarely, malignant tumors must however always be considered. The differential diagnosis on imaging may be difficult to establish between bone tumors and chronic infection. Surgical biopsy is therefore often performed to establish the precise origin of the fracture. We report the case of an adamantinoma (osteofibrous dysplasia-like) of the fibula in a 7-year-old child, discovered during the management of a pathologic fracture. The presumed diagnosis before biopsy was chronic osteomyelitis. A 14-cm-resection of the affected fibula was performed with good functional result. Differential diagnosis between adamantinoma, osteofibrous dysplasia and osteofibrous dysplasia-like adamantinoma remains very challenging.