Xanthoma of Tendoachilles: A case report
A 28-year-old female presented to the outpatient department with complaints of swelling over the posterior and distal aspect of the left leg just above the heel for 2 years and pain for 2 months with difficulty walking. It was insidious in onset without any history of trauma, gradually progressive and aggravated on walking, and relieved on rest. On examination, a firm swelling of size 6 × 3 × 2 cm on the TA tendon was present 2 cm proximal to the insertion site (Fig. 1a). It was globular in shape, the skin over the swelling was smooth with the normal surrounding skin. There was no local rise of temperature, the swelling was non-tender, non-reducible and non-translucent, and non-adherent to skin. The lesion was in the tendon and was moving along the movement of the tendon. In the left ankle, terminal dorsiflexion was painful and restricted by 10° in comparison to the opposite side (30°). The patent had an antalgic gait. There was no motor weakness or sensory loss of the bilateral leg.

X-ray of heel showed soft tissue shadow without the involvement of bone (Fig. 1b). Ultrasonography of the swelling showed a homogenous hypoechoic lesion inside the TA. The magnetic resonance imaging of the left ankle showed swelling (hyperintensity structure) of 6 × 3 × 2 cm, arising from TA (Fig. 1c) suggestive of tendon xanthoma (TX). After clinical and radiological examination, the provisional diagnosis was made as TX with differential diagnosis as cholesterol accumulation, tendonitis, peritendinitis or bursitis, trauma, nodules from rheumatic arthritis, or gout tophi. The patient was advised for general medicine consultation for further investigation and medical management because of TX. Her Total cholesterol level was 361 mg/dL, and the total LDL-C level was 277 mg/dL as per the laboratory report. Her mother was having hyperlipidemia and under treatment for the same. She was diagnosed as heterozygous FH and she was put on atorvastatin 20 mg once daily as suggested by the concerned physician.

Her LDL-C level was 198 mg/dL after 3 weeks of atorvastatin therapy. There was no reduction in the size of the swelling after 3 weeks. There was pain due to the mechanical block on the dorsiflexion of the foot and the patient was uncomfortable during walking. The swelling was intervened surgically due to persistent pain and gait disturbance. Intraoperatively, full-thickness involvement was found and the total excision of the affected part was done through the posterior approach and sent for histopathological examination. In the neutral position of the ankle, a gap of about 6 cm was created due to excision of the affected part and that was reconstructed by harvesting a short FHL graft and transfixing with a bioabsorbable interference screw through the calcaneum (Fig. 2b). Histopathological examination confirms our diagnosis of TX. Macroscopically, it showed a cut section which was firm, solid, and greyish-yellow in color. On the microscopic section, fibrocartilaginous tissue infiltrated by foamy histiocytes was seen. There were large areas of cholesterol cleft surrounded by foreign body giant cells. A below-knee splint was applied dorsally in plantar flexion position for 2 weeks. The dressing was done on the 2nd and 5th day, which was clean and healthy, and the suture was removed on day 14th. A boot cast in plantar flexion was applied for the next 2 weeks followed by in neutral position for 2 weeks with partial weight mobilization with a walker. The patient was allowed for full weight-bearing mobilization after 6 weeks of surgery. The patient was able to stand on her toe at 4 months. The patient was followed up every month and at the end of 1 year, there was no recurrence.