Review Question - QID 215758

This patient has a heterogeneous soft tissue mass in her lateral thigh with a non-diagnostic core needle biopsy. Of the options available, the best next step would be an open biopsy directly through the vastus lateralis muscle.

Biopsy principles in orthopedic oncology are important to prevent unnecessary morbidity and mortality in patients, due to the general belief that tumor cells will contaminate the biopsy tract and/or open biopsy incision. Principles to follow include longitudinal incisions, do not expose neurovascular structures, maintain hemostasis, approach through the involved compartment, and drain placement, if necessary, in line with the surgical incision. These prevent unnecessary contamination and allow for better definitive surgery planning.

Sim et al. published a review article on the diagnosis, evaluation, and management of soft-tissue tumors. They discuss imaging studies, clinical presentation, biopsy techniques, and treatment considerations. Fundamentals of open biopsying include proper incision location and orientation, minimal flap formation, avoiding intermuscular planes and neurovascular structures, and meticulous hemostasis prior to closure.

Traina et al. review techniques for successful surgical planning for biopsy of musculoskeletal tumors. They discuss fine needle aspiration, core needle biopsy, and open biopsies. With all biopsies, the objective is to obtain a diagnostic histological tissue sample without tumor spread. This includes not violating anatomic planes, compartmental barriers, joint space, and tissues around neurovascular bundles.

Figure A demonstrates an AP right femur and hip X-ray without significant findings. Figure B demonstrates a T2 contrast-enhanced axial MRI of the thigh with a heterogeneous mass involving likely the vastus lateralis predominately. Figure C is a coronal T2 contrast-enhanced coronal MRI demonstrating the same heterogenous lateral thigh mass.

Incorrect Answers:
Answer 1: Fine need aspiration has a high false-negative rate and compromises tissue architecture. An open biopsy would be a better open after a non-diagnostic core-needle biopsy.
Answer 2: While repeat core-needle biopsy can be performed after a non-diagnostic sample, it should not be done in a new direction due to concern of possible contamination of another compartment.
Answer 3: Resection should be delayed until a diagnosis has been determined. This patient's imaging and clinical story are concerning for a sarcoma, which is usually treated with wide resection not marginal resection.
Answer 5: Hip disarticulation may be a treatment option after diagnosis has been determined. However, treatment should be delayed until after a diagnosis has been determined.