A 35-year-old woman presented to my office with the chief complaint of a large growth on the dorsolateral left foot. She denied any prior treatment for it. She could not wear a closed-in shoe due to pain and irritation to the mass. Her shoe gear was limited to flip-flops. She denied any injury to the foot. The mass had been growing slowly for five years or more. She denied any fluctuations in the size of the mass over time. She also related that she had a growth on her right pinky finger.
A review of systems and her past medical history revealed she was healthy without any prior medical problems, hospitalizations or bodily injuries. She was not taking any maintenance medications, had no allergies and had no prior surgical history. Her family and social history revealed that she was born in Vietnam and moved to the United States in 1980.
A general examination of the patient revealed a healthy, petite Asian female at 63 inches tall and weighing 98 lbs. Her podiatric examination revealed strong palpable pulses with skin pink and warm to the touch. Her capillary refill was brisk to the toes. The neurologic exam revealed symmetric and equal deep tendon reflexes of the patella and Achilles. The epicritic sensation was intact to the level of the toes.
The dermatologic exam revealed a large mass on the dorsolateral left foot measuring 3.5 cm x 3.0 cm in proximity to the fifth tarsometatarsal joint. The mass was firm with a rubbery type feel and had no fluctuance. The orthopedic exam revealed no particular tenderness with palpation of the mass. There was no pain with range of motion of the ankle, subtalar, midtarsal or toe joints.
X-rays failed to reveal any osseous involvement. Soft tissue shadowing of the mass was visible. Magnetic resonance imaging (MRI) revealed a soft tissue lesion measuring 2.1 cm x 1.7 cm x 3.4 cm. The lesion was located between the fourth and fifth metatarsal bases. The lesion had an intermediate to isointense signal to muscle on the T-1 weighted images. There was a heterogeneous signal on the STIR images. The lesion appeared to be communicating to the joint space of the fourth and fifth metatarsal and cuboid. There were also erosive bone changes that I believed were the result of pressure. Finally, multiple erosive changes were present throughout the midfoot.
The differential diagnosis provided by the radiologist included schwannoma, a myxoid lesion, or a synovial-based lesion.
Blood work obtained prior to the MRI was remarkable for a complete blood count of 6.1 K/uL, red blood cells 4.46 M/UL, hemoglobin 12.2 g/dL, hematocrit 37.6%, platelets 275 K/UL, glucose 89 mg/dL, BUN 9 mg/dL, keratinize 0.9 mg/dL and sedimentation rate of 76 mm/hr. Her uric acid was 10.6 mg/dL, rheumatoid factor was <7 IU/mL, and antinuclear antibody screen was negative.
The patient elected to have an excisional biopsy of the mass. Intraoperatively, there was a septated mass with a white, chalky appearance. The mass clinically appeared to be gout and the pathology report revealed numerous polarizable crystals consistent with monosodium urate.
Gout is a crystalline arthritis that we typically associate with middle-aged men. Often, patients have concomitant health conditions such as diabetes, metabolic syndrome, a cardiac history of hypertension, coronary artery disease and obesity. Women typically are prone to gout at a post-menopause age and/or are prone when taking thiazide diuretics. This case of tophaceous gout proved to be in an unlikely patient demographic.