Teaching Case

presented with a mass at the plantar aspect of the right foot. Clinical examination showed a firm bulging mass, insensitive on palpation and measuring 11 x 15 cm. The patient had an excision of a soft tissue mass at the same location 7 and 13 years before. Subsequently plain radiograph, ultrasonography, CT scan and Magnetic Resonance Imaging were carried out.

A 25-year-old male presented with a mass at the plantar aspect of the right foot. Clinical examination showed a firm bulging mass, insensitive on palpation and measuring 11 x 15 cm. The patient had an excision of a soft tissue mass at the same location 7 and 13 years before. Subsequently plain radiograph, ultrasonography, CT scan and Magnetic Resonance Imaging were carried out. Location, clinical history and cross-sectional imaging of the soft tissue mass suggest the diagnosis of plantar fibromatosis (Ledderhose's disease).

Superficial fibromatosis includes plantar fibromatosis (Ledderhose's disease), palmar fibromatosis (Dupuytren's contracture), penile fibromatosis (Peyronie's disease), and knuckle pads. Clinically Ledderhoses's disease presents as a mostly unilateral, nonencapsulated, locally invasive neoplasm, characterized by focal proliferation of fibroblasts in the subcutaneous tissue of the foot sole. This benign lesion may recur with more aggressive features if incompletely resected. The etiology of Ledderhose's disease is unknown. Many factors have been postulated including endocrinopathy, trauma, neuropathy, biochemical and metabolic imbalance, faulty development, infection and patient's occupation. Most of the lesions are asymptomatic and discovered by palpation. Sex ratio is 1:1 with a predilection for young adults and a peak incidence between 25 and 35 years. It has been occasionally reported in children. MR imaging gives useful preoperative information on location and extent of the lesion including differentiation from other pathological entities. MR imaging may also contribute to predict composition of the lesion, based upon vascularity and cellularity throughout the tumor. Lesions that are predominantly hypointense on spin-echo images, are probably markedly hypocellular and fibrotic. On the other hand, a high signal intensity is due to hypercellularity of the mass, which occurs in more early stages. For some authors, a round or oval, inhomogeneous mass at the foot sole with well-defined margins and a signal intensity between skeletal muscle and subcutaneous fat are characteristics that make plantar fibromatosis unique. However, some lesions may have similar intensity characteristics, such as callus, scarring, and fibrotic changes in the subcalcaneal fat.