Osteofibrous Dysplasia of Humerus: An Unusual Presentation of a Rare Lesion

Osteofibrous dysplasia (OFD) is a benign fibro-osseous lesion, and it comprises 0.2% of all primary bone tumors. It occurs most commonly in infancy and childhood and most commonly involves the tibia/fibula. The most frequent site is the cortical bone of the anterior midshaft of the tibia, and involvement of other long bones, such as the humerus, ulna, radius, and clavicle are extremely rare. It is usually managed conservatively but surgical intervention is needed in cases with a pathological fracture or significant deformity. We report a rare case of OFD in a 7-year-old male child occurring in the meta-diaphyseal region of the proximal humerus, with recurrence of the lesion and secondary aneurysmal bone cyst (ABC) changes who underwent three surgical procedures and still has a persistent residual lesion.

A 7-year-old male presented to us with a history of right proximal arm swelling and pain for 2 years. He had a history of multiple episodes of trivial trauma, elsewhere managed twice conservatively, and surgical intervention performed once 1 year back. On physical examination, he was found to have well-defined, bony hard, immobile swelling with irregular margins involving the proximal arm extending up to midarm. The patient had restricted abduction and forward flexion with a 2 cm shortening of the right arm. There was no local rise in temperature, no bony tenderness, no muscle wasting, and no neurovascular deficit. The radiograph showed a large osteolytic lesion involving the meta-diaphyseal region, measuring 70 × 40 mm, showing a narrow zone of transition with distinct borders, no cortical breach, no periosteal reaction, and a significant humerus varus ([Fig. 1A]). Magnetic resonance imaging (MRI) sequences showed a multiloculated hyperintense expansile lytic lesion with a narrow zone of transition, cortical thinning, and intralesional bony septations, measuring 7.2 × 3.9 × 3.7 mm involving the meta-diaphyseal region of the proximal humerus, with focal physeal breach and epiphyseal extension, suggestive of fibrous dysplasia ([Fig. 1B]). Considering the age and clinicoradiological features, surgical intervention was done in the form of curettage, corrective osteotomy, bone grafting (fibular strut allograft and cancellous allograft), and stabilization by Joshi External Stabilization System (JESS), and a tissue sample was sent for histopathological examination.

Fig. 1 (A) Radiograph of the proximal humerus showing osteolytic lesion in the meta-diaphyseal region with thinning of the cortex but no breach. (B) Magnetic resonance imaging sequence showing multiloculated hyperintense expansile lytic lesion with a narrow zone of transition, cortical thinning, intralesional bony septations involving the meta-diaphyseal region. (C) Histopathology examination shows anastomosing irregular bone lined uniformly by osteoblasts, abutting abundant fibrous tissue, numerous loops, and hoops of bone fusing with each other, and reactive giant cells in the fibrous component. (D) A 5 years follow-up radiograph showing complete healing of the lesion with TENS in situ.

Histopathological examination showed anastomosing irregular bone lined uniformly by osteoblasts, abutting abundant fibrous tissue, numerous loops, and hoops of bone fusing with each other, and reactive giant cells in fibrous component and reported to be OFD ([Fig. 1C]). Immediate postoperative follow-up was uneventful, and JESS was removed and was on periodic regular follow-ups. Complete healing of the lesion was seen at a 6-month follow-up radiograph. At 2 years follow-up, the X-ray showed recurrence of the lesion. A repeat MRI with computed tomography correlation was done that confirmed the recurrence of the lesion with secondary ABC changes. He was planned for curettage, bone grafting (cancellous allograft), and additional stabilization by a 4 mm titanium elastic nailing system (TENS) nail. The repeat biopsy sample showed OFD with a secondary aneurysmal bone cyst. He was on regular annual follow-up and showed complete healing at 4 months follow-up ([Fig. 1D]) and in the third year post-second intervention, he had a recurrence of the lesion. He is asymptomatic now and has a 3 cm shortening of the right arm.

To date, only five cases of OFD occurring in the humerus have been reported. Among these, three were in the first decade of life and two in adulthood. In all, three children and one of the adults, the tumor was reported to be diaphysis, and in another patient, the tumor location was not specified.

Progression of the OFD lesion halts at skeletal maturity, but some authors have reported occurrence and progression after skeletal maturity as well. In literature, conservative management is recommended. However, in cases with pathological fracture, or significant deformity, surgical intervention has been recommended. Due to the profound association between OFD and adamantinoma, some advocate resection of the entire lesion. Lee et al[1] retrospectively reviewed 16 patients with OFD of the tibia with diversified management depending on the severity of symptoms and extent of the lesion and concluded that surgical treatment should be more radical, whereas Westacott et al[2] in their study of 28 cases of OFD over 13 years have not observed the transformation of OFD to adamantinoma and recommend a conservative approach. Because of the extreme rarity of the OFD and limited literature on management of OFD, management remains controversial, because of which surgeons have different approaches to management.

OFD, though rare, can occur in sites other than the tibia and we report a recalcitrant case of OFD of the humerus. It is a pathological diagnosis that could be picked up by an experienced pathologist and should be suspected in any patient with recalcitrant fibrous dysplasia.

Informed Consent

Written consent for publication of patient details was obtained from the parent/guardian.

Authors' Contributions

K. Venkatadass was involved in the conceptualization of the technique and surgeon who operated and reviewing the manuscript. Deepak Jain contributed to manuscript preparation, figures, literature review, and artwork. Owais Ahmed contributed to manuscript preparation, figures, and literature review. S. Rajasekaran reviewed and edited the manuscript.

Publikationsverlauf

Artikel online veröffentlicht:
14. Oktober 2022

• References:

• 1 Lee RS, Weitzel S, Eastwood DM. et al. Osteofibrous dysplasia of the tibia. Is there a need for a radical surgical approach?. J Bone Joint Surg Br 2006; 88 (05) 658-664
• 2 Westacott D, Kannu P, Stimec J, Hopyan S, Howard A. Osteofibrous dysplasia of the tibia in children: outcome without resection. J Pediatr Orthop 2019; 39 (08) e614-e621