A Thigh Mass Associated With a Total Hip Replacement in a 69-Year-Old Woman

A 69-year-old woman presented with a 6-month history of a localized swelling in the lateral aspect of her left midthigh and mild thigh discomfort exacerbated by walking. She had a left total hip replacement for osteoarthritis 10 years earlier. A Ti alloy press-fit acetabular component (Shearer, Orthotech Ltd, Loughborough, United Kingdom) and a Ti alloy cemented stem (Ultima, Johnson & Johnson, Leeds, United Kingdom) were used. The cup was revised for aseptic loosening 5 years postoperatively, using a cemented all-polyethylene component. The patient’s medical history included breast carcinoma, for which she was treated by mastectomy 4 years earlier, with no subsequent local recurrence or metastatic disease.

On examination, a rounded 7-cm diameter soft tissue mass was palpable in the lateral aspect of the left thigh. The mass did not feel fluctuant or compressible, was fixed and slightly tender, and appeared to lie deep to the vastus lateralis muscle. There was no associated alteration in local temperature, skin changes, or local lymphadenopathy. The patient walked with a cane and had a positive Trendelenburg sign. Examination of the left hip revealed no fixed flexion deformity, 80° flexion limited by discomfort, 30° abduction, 20° adduction, 20° external rotation, and 0° internal rotation. The physical examination otherwise was unremarkable. Routine blood investigations including full blood count, C-reactive protein, erythrocyte sedimentation rate, electrolytes, and bone and liver profiles were normal.