Idiopathic non-familial acro-osteolysis: a rare case report.

A 25-year-old woman patient presented with shortening of fingers with racket nails and numerous yellowish papules over the hands and forearms for 21 years. X-ray of the hands revealed destructive osteolytic changes in all the terminal phalanges. Skin biopsy from the yellowish papules showed epidermal proliferation, perivascular mononuclear infiltrate, thickening of dermal collagen, septal fibrosis and loss of adipocytes mimicking sclerodermatous changes in the dermis and hypodermis. The patient did not have any history of similar illness in the family or occupational exposure to vinyl chloride. After excluding all other possibilities of acral-osteolysis, we diagnosed the case as idiopathic non-familial variety of acro-osteolysis. This is a rare entity characterized by terminal resorption of fingers, sometimes associated with Raynaud's phenomena and yellowish cutaneous papules.

What was known?

1. The idiopathic non-familial acro-osteolysis is an extremely rare condition.

2. There is slow resorption of the terminal phalanges of the hands.

3. Associated with other bone defects, Raynaud's phenomena and yellowish papules and plaques in the arms.

Introduction

Acro-osteolysis refers to destructive lytic changes on the distal phalanges. There are three types of acro-osteolysis: Familial; idiopathic, non-familial; and occupational. The idiopathic non-familial variety is an extremely rare condition where there is slow resorption of the terminal phalanges of the hands, which may sometimes be associated with other bone defects, Raynaud's phenomena and yellowish papules and plaques in the arms.[1] We describe herein a case of idiopathic non-familial acro-osteolysis that had associated yellowish papular lesions in the forearms and hands with scleroderma-like histopathological changes.

Case Report

A 25-year-old lady presented to us with complaints of shortening of fingers of the hands, deformity of nails and yellowish papules in the hands and forearms for 21 years. The patient's complaints started early in childhood, with asymptomatic shortening of terminal phalanges in a couple of fingers of insidious onset that gradually involved all fingers of the hands. However, the toes remained unaffected [Figure 1]. At almost the same time, the patient started developing asymptomatic papules in the hands. At presentation, the patient had non-follicular yellowish papules in the fingers, hands and elbow extensors, mostly discrete but some of them coalescing to form a confluent appearance [Figure 2]. The terminal phalanges were extremely short, with a relative broadened appearance. The patient's nails resembled racket nails. The patient had no history of Raynaud's phenomena, any bleeding disorders, occupational exposure to vinyl chloride gas and hobby of playing guitar or any other musical instruments or any other recurrent trauma. Menstrual history was normal. Detailed cutaneous and systemic examination failed to detect palmoplantar keratoderma, hirsuitism, dental abnormality or any other musculoskeletal abnormality.

Figure 1

Hands showing shortened distal phalanges, racket nails and yellowish papules near the knuckles

Figure 2

Yellowish papules in the elbow extensors

Routine investigations including blood counts, hepatic and renal function tests, calcium level and parathyroid hormone status and ultrasonography of the abdomen were within normal limits. Antinuclear Antibodies (ANA) were negative. Roentgenogram of the hands showed destructive osteolytic changes in the terminal phalanges of all 10 fingers [Figure 3]. A biopsy for histopathology was taken from the yellowish papule revealing hyperkeratosis, focal parakeratosis and acanthosis of epidermis. The dermis was thickened, with abundant collagen bundles surrounding the eccrine coils. The hypodermis was characterized by loss of adipocytes and septal thickening associated thickened eosinophilic collagen bundles [Figure 4]. Histopathology of the papules resembled sclerodematous changes. Correlating clinical findings with laboratory evidence finally, we could diagnose the case as an idiopathic non-familial variety of acro-osteolysis.

Figure 3

X-ray of the hands showed lytic changes in fingers

Figure 4

(10× magnification) Hematoxylin and eosin stain, showing non-specific epidermal proliferation, increased dermal collagen and increased septal thickening in the hypodermis

Discussion

Radiological appearance of phalangeal osteolysis can be divided into three major groups. In the first group, there is resorption of terminal tufts, which included diseases like scleroderma, Raynaud's disease, sarcoidosis, psoriatic arthropathy, neuropathic disease, hyperparathyroidism, porphyria, progeria and pachydermoperiostosis. In polyvinyl chloride tank cleaners, Haidu-Cheney syndrome and Rothmund's syndrome, there is resorption of the mid-portion of the phalanges. In the third category of diseases with phalangeal osteolysis, which includes multicentric reticulohistcytosis, there is periarticular resorption.[2] After ruling out all other possibilities, our differential chiefly included Haim-Munk syndrome, Hajdu-Cheney syndrome and acro-osteolysis.

Haim-Munk syndrome is an autosomal-recessive disorder of keratinization, where there is a mutation in lysosomal protease Cathepsin C gene.[3] The condition is characterized by palmoplantar hyperkeratosis, severe early onset periodontitis, onychogryphosis, pes planus, arachnodactyly and acro-osteolysis.[4] Hajdu-Cheney syndrome was first described in 1948 by Hajdu and Kauntze,[5] and more extensively reported by Cheney.[6] Most cases are sporadic, but inherited cases are likely to be autosomal dominant. This condition is characterized by craniofacial anomalies, musculoskeletal anomalies including elongated and bowed (serpentine) fibulae and acral osteolysis. Polycystic kidneys are associated in this condition. This association of anomalies is referred to as serpentine fibula polycystic kidney syndrome.[7]

Acro-osteolysis can be familial, idiopathic or occupational. Familial acro-osteolysis affects only the feet and is associated with plantar ulcerations.[8] The occupational variety is due to chronic exposure to vinyl chloride gas, and it affects mainly the fingers of the hands. This variant shows indurations of skin and Raynaud's phenomena.[9]

Idiopathic non-familial variant usually affects the fingers and usually shows progressive acro-osteolysis of the hands combined with progressive mandibular ramus osteolysis and multiple cortical defects.[10] This is an extremely uncommon disease, and there are only very few published cases in the English literature.[1011] This variant may also be associated with Raynaud's phenomena. Only one case has been described to the best of our knowledge, with cutaneous lesions consisting of numerous yellow papules 2–4 mm in diameter and showing a linear distribution and coalescence into plaques, mainly on the arms.[8]

Our case was a young lady with idiopathic non-familial acro-osteolysis of the hands who did not have any associated Raynaud's phenomena or musculoskeletal defects but had very characteristic yellowish papules in the forearms and hands with additional feature of racket nails.

What is new?

1. Idiopathic non-familial acro-osteolysis did not have any associated Raynaud's phenomena or musculoskeletal defects.

2. Yellowish papules in the forearms and hands had scleroderma-like histopathological changes.

3. Additional feature of racket nails.