Plexiform neurofibroma with massive hand involvement

Abstract

An 11-year-old African American boy with neurofibromatosis type I (NF-1) has suffered from an enlarging mass involving his left hand and distal forearm since the age of 18 months. This large plexiform neurofibroma invests the majority of the distal portion of the median nerve of the left arm and hand. The left hand and distal forearm contained a large soft tissue mass, which completely obscured the normal morphology of the hand. The distance between the tip of the thumb and the tip of the fifth finger measured 17.5 cm and from the base of the thumb to the base of the fifth finger measured 29 cm. From the proximal interphalangeal joint of the second finger to the first crease of his wrist measured 17 cm (Fig 1). There was moderate atrophy of the left upper extremity; the right forearm and biceps each had a circumference that was 2.5 cm larger than those on the left side. The patient was unable to grasp objects with the left hand but could move all of his fingers. He had decreased sensation to pinprick over the second, third, and fourth digits. A recent magnetic resonance image of the left hand and arm demonstrated a large conglomeration of smaller, nodular masses in the left hand and wrist with pronounced mass effect; there was extension of the neoplasm between the first, second, and third digits at the level of the metacarpal bodies and heads. This patient has undergone two debulking surgeries with left carpal tunnel decompression and neurolysis for relief of intermittent paresthesias and pain. He is having increasing difficulty with his fine motor skills, especially apposition of the digits of the left hand. It is becoming increasingly difficult for him to use his left hand, and, at times, he must use his right hand to help position the left one appropriately. Despite surgery and intensive occupational therapy to improve use of the hand, the patient's functional capabilities have failed to improve and are deteriorating. Therapeutic options for this patient are limited, and distal amputation of the left forearm may become unavoidable. Cutaneous neoplasms are common in neurofibromatosis type I, especially the plexiform neurofibroma, the most common peripheral nerve sheath tumor.1Riccardi VM Neurofibromatosis: phenotype, natural history, and pathogenesis. : The Johns Hopkins University Press, Baltimore1992Google Scholar These growths involve deeply located nerves and carry approximately a 5% risk of malignant transformation.2Needle MN Cnaan A Dattilo J et al.Prognostic signs in the surgical management of plexiform neurofibroma: the Children's Hospital of Philadelphia experience, 1974-1994.J Pediatr. 1997; 131: 678-682Abstract Full Text Full Text PDF PubMed Scopus (175) Google Scholar Hyperpigmentation or hypertrophy of the soft tissues overlying these growths is not uncommon.3Roos KL Muckway M Neurofibromatosis.Dermatol Clin. 1995; 13: 105-111Abstract Full Text PDF PubMed Scopus (95) Google Scholar Neoplasm size may range from small, never requiring any treatment, to massive growths with considerable impairment of functional capabilities. Depending on the location of the tumor, symptoms may vary. Tumors arising in an extremity, for example, may become hypertrophied, severely limiting use of the limb as in our patient. Signs indicative of malignant degeneration include a sudden increase in size of the mass, pain in a previously quiescent lesion, or thickened, nodular protuberances growing within the mass.4Williams GD Hoffman S Schartz IS Malignant transformation in a plexiform neurofibroma of the median nerve.J Hand Surg. 1984; 9: 583-587Abstract Full Text PDF PubMed Scopus (10) Google Scholar Surgical exploration and biopsy are indicated in these situations to rule out development of neurofibrosarcoma. Our patient has undergone extensive evaluation for possible amputation with placement of a functional prosthesis, but thus far the family has refused this option.