Melorheostosis in the pediatric hand

Key Clinical Message

It is important to consider the rare case of a melorheostosis in patients presenting with soft tissue swelling, joint contractures, and “dripping candle wax”‐like hyperostoses visible on hand radiographs. Clinical sequelae such as carpal tunnel syndrome or trigger finger have to be ruled out. Symptomatic therapy is usually sufficient.

1. QUESTION

A 9‐year‐old female patient presented with a painless, volar swelling of her left ring finger, palm, and mild active extension deficit in the proximal interphalangeal joint (Figure 1). There was no tenderness upon palpation of the swollen ray and palm present. The hand radiographs revealed a “dripping candle wax”‐like hyperostosis in the proximal phalanges and metacarpals of the third and fourth fingers (Figure 2). The hyperostosis was located in the cortices and seemed to encroach toward the intramedullary canal of the affected bones. MRI sequences confirmed the compact, sclerosing structure of the bone lesions without any affection of the nearby flexor tendons (Figure 3). No further blood tests were obtained. What is the diagnosis?

Figure 1.

Clinical image of her affected hand/palm showing volar swelling of her left ring finger, palm, and mild active extension deficit in the proximal interphalangeal joint

Figure 2.

Dorsopalmar hand radiograph showing the pathognomonic “dripping candle wax”‐like hyperostosis

Figure 3.

T1 (A, C)‐ and fat‐suppressed proton‐density‐weighted turbo spin‐echo magnetic resonance imaging (B) showing the pathology and soft tissue affection

2. ANSWER

The diagnosis was melorheostosis, a very rare disease, whose exact etiology has not yet been identified. It occurs equally in males and females, and its main features involve dermal and soft tissue abnormalities besides the anomalous bone formation.1 It is often diagnosed incidentally and may involve different skeletal regions such as vertebrae, sternum, or upper and lower extremities.2 Soft tissue swelling and fibrosis may consequently lead to sequelae with clinical symptoms such as carpal tunnel syndrome or trigger finger. However, the diagnosis is usually confirmed by native radiographs; MRI or bone scintigraphy may be beneficial in certain cases to delineate soft tissue affections or search for multiple foci. Potential differential diagnoses comprise myositis ossificans, osteoma and (parosteal) osteosarcoma, and posttraumatic or postinfectious sequelae. It may also appear with a concomitant osteopoikilosis, osteopathia striata, or malformations of blood vessels/lymphatics.

The patient described in this report received symptomatic therapy (occupational and eventually splinting therapy) which improved her clinical situation over the course of the following years although swelling persisted. Hand splints had to be worn for several months. Previous reports have moreover reported about successful results after therapy with bisphosphonates, rheologic and nonsteroidal anti‐inflammatory drugs. In selected cases, surgical therapy may be indicated to remove the sclerotic cortex or decompress the median nerve. Regular follow‐up native radiographs showed no changes in the pathology throughout the course.

CONFLICT OF INTEREST

None declared.

AUTHOR CONTRIBUTION

SF: wrote the manuscript.

Farr S. Melorheostosis in the pediatric hand. Clin Case Rep. 2019;7:1110–1111. 10.1002/ccr3.2160