Painless osteoid osteoma of the middle phalanx

P A I N L E S S O S T E O I D O S T E O M A OF T H E M I D D L E P H A L A N X C. REX, L. JACOBS and Z. NUR

From the Royal Oldham Hospital, Oldham, UK A 12-year-old girl with a painless swollen finger was a clinical puzzle as her presentation and X-rays were not typical of osteoid osteoma. Computed tomography and histology confirmed the diagnosis. This case is reported for its atypical presentation, difficulty in diagnosis and rare occurrence in the middle phalanx.

Journal of Hand Surgery (British and European Volume, 1997)22B: 6:798-800 CASE REPORT

A 12-year-old girl presented with swelling of the right ring finger of 3 months duration which was gradually getting bigger. There was no pain but an occasional sensation of warmth was felt in the finger at night. There was no history of injury or any constitutional symptoms. Clinically there was a fusiform swelling of the middle phalanx which was not tender to touch (Fig 1). The swelling was thought to have both bony and soft tissue components. An X-ray of the finger showed a faint loss of bone structure with slight coarsening of the bone which was non-specific (Fig 2). The possibility of periosteitis could not be ruled out although the full blood count, ESR, Wasserman reaction and Mantoux test were normal. Bone scan showed an increased uptake in the middle phalanx and distal interphalangeal joint region (Fig 3). MR scan at this stage showed an abnormal marrow signal predominantly in the middle and distal portion of the middle phalanx (Fig 4). There was associated soft tissue swelling and widening of the distal interphalangeal joint. As the diagnosis was uncertain, an open biopsy was done but the histology report was inconclusive. Bacterial cultures, including that for tuberculosis, were negative. Two months after the biopsy, the swelling got bigger and a CT scan was done. This clearly showed a dense sclerotic focus with a surrounding translucent zone

Fig 2 X-ray showing faint loss of bony trabeeulae at the distal end of the middle phalanx Fig 1 Swelling in the region of the middle phalanx of the ring finger 798

OSTEOID OSTEOMA OF MIDDLE PHALANX

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Fig 4 M R scan showing an abnormal marrow signal in the middle phalanx of the ring finger

Fig 3 Bone scan showing increased uptake in the middle phalanx

Fig 6 Five m o n t h s after operation there is no significant swelling

Fig 5

C T scan showing the central nidus of the osteoid osteoma

at the distal end of the middle phalanx (Fig 5), consistent with an osteoid osteoma. This was treated by excision and curettage. The biopsy confirmed an osteoid osteoma. The patient is symptom free, with subsidence of swelling and full range of movements 5 months later (Fig 6). DISCUSSION Osteoid osteoma is a benign bone tumour usually affecting those between 10 and 30 years of age, with bones of

the lower extremities being predominantly involved. It is more common in men by a ratio of two to one (Healey and Ghelman, 1986). The average duration of symptoms before diagnosis in patients with a lesion in the hand and wrist is 13 to 15 months (Bednar et al 1993; Doyle et al, 1985). Bednar et al, in their extensive review of 46 patients with upper limb osteoid osteomas noted absence of this lesion in the middle phalanx. Ambrosia et al (1987) also pointed out that the least common site of osteoid osteoma in the upper limb is the middle phalanx. The lesion presents characteristically with pain, frequently in the night, which is relieved by salicylates in 73% of patients (Healey and Ghelmans 1986). It presents in phalanges with a fusiform swelling due to the subcutaneous location. In the majority, X-ray examination provides the diagnosis. Bone scan usually identifies a lesion that cannot be seen on X-rays although a negative

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radionuclide scan has been reported in osteoid osteoma (Fehring and Green, 1984). Computed tomography is used most often to diagnose and identify the location of an osteoid osteoma in planning surgical resection (Blankstein et al, 1985). MR scan of hands is non-specific in differentiating florid reactive periosteitis from low grade infection and small osseous neoplasms like osteoid osteomas (Ehara et al, 1994). The differential diagnoses includes chronic osteitis, Ewing's sarcoma, osteosarcoma and non-ossifying fibroma. The treatment is primarily by excision and curettage. Surgical cure is believed to follow complete removal of the nidus. The majority of persistent lesions after surgery have been in the hands (Ambrosia et al, 1987; Bednar et al, 1993). References Ambrosia J M, Wold L E, Amadio P C (1987). Osteoid osteoma of the hand and wrist. Journal of H a n d Surgery, 12A: 794-800.

THE J O U R N A L OF H A N D SURGERY VOL. 22B No. 6 D E C E M B E R 1997 Bednar M S, McCormack R R, Glasser D, Weiland A J (1993). Osteoid osteoma of the upper extremity. Journal of H a n d Surgery, 18A: 101%1028. Blankstein A, Morag B, Apter S, Engel J (1985). Diagnosis of osteoid osteoma using computerized tomography. Journal of H a n d Surgery, 10B: 407-408. Doyle L K, Ruby L K, Nalebuff E G, Belsky M R (1985). Osteoid osteoma of the hand. Journal of Hand Surgery, 10A: 408-410. Ehara S, Nishida J, Abe M, Mizutani H, Ohba S (1994). Magnetic resonance imaging of pseudomalignant osseous turnout of the hand. Skeletal Radiology, 23:513-516. Fehring T K, Green N E (1984). Negative radionuclide scan in osteoid osteoma: a case report. Clinical Orthopedics and Related Research, 185: 245-249. Healey J H, Ghelman B (1986). Osteoid osteoma and osteoblastoma: Current concepts and recent advances. Clinical Orthopedics and Related Research, 204: 76-85.

Received: 9 April 1997 Accepted after revision: 2 June 1997 Mr C. Rex, 1 Barton Avenue,Urmston, Manchester M41 5PS, UK. © 1997The British Society for Surgery of the Hand