Recurrent Intramuscular Hematomas in a 40-Yr-Old Female Renal Transplant Recipient
A 40-yr-old woman with lupus with anticoagulant positivity and end-stage renal disease status after right-sided kidney transplantation complicated by retroperitoneal hematoma and lumbar plexopathy presented with recurrent right medial thigh intramuscular (IM) hematomas. The first IM hematoma occurred 1 yr after transplant following leisurely horseback riding. Her examination was significant for ecchymosis from the right pubis to the medial midthigh, 4/5 pain-limited hip flexion and adduction strength, 5/5 knee flexion and extension strength, with intact sensation and reflexes throughout. Ultrasound (US) revealed an IM adductor longus hematoma measuring 6.3 × 12.9 × 2.2 cm (Fig. 1). Computed tomography of the right lower extremity excluded other pathology, such as sarcoma. She was managed conservatively with acetaminophen for pain and continued her home exercise program focusing on lumbopelvic, gluteal, hip flexor, and adductor strengthening. Ultrasound-guided aspiration was offered for persistent or worsening symptoms. However, the hematoma self-resolved in 2 mos.
A year later, she returned with right medial thigh pain, swelling, and bruising after performing adductor stretching at home. Her examination was significant for right medial thigh ecchymosis with 5/5 strength and preserved reflexes and sensation throughout. High-resolution diagnostic US of the lower abdomen and medial thigh was notable for an IM gracilis hematoma measuring 3.5 × 16.6 × 1.6 cm (Fig. 2A). Side-to-side comparison revealed hyperechoic, atrophic appearance of the right gracilis, adductor magnus (Fig. 2B), and internal oblique (Fig. 2C) muscles and subtle echogenic changes with decreased bulk of the right adductor longus and brevis muscles (Fig. 2D) compared with the left. These right-sided findings were possible sequelae of fibrous scarring after severe, recurrent muscle injury and/or lumbar plexopathy diagnosed 2 yrs prior. The right iliohypogastric, ilioinguinal, and obturator nerves, as well as the iliacus and quadriceps muscles, appeared normal. Her second hematoma self-resolved in 4 wks with no residual functional deficits.
- Normal muscles have a characteristic “starry night” appearance on US with hypoechoic muscle fibers arranged in fascicles, interspersed with hyperechoic perimysium.1,2 After denervation changes, muscle tissue appears grossly hyperechoic because of atrophy and loss of hypoechoic muscle fibers.1
- After severe or recurrent muscle injury, fibrous scars may form, appearing as focal, hyperechoic linear, or stellate lesions, whereas the majority of surrounding muscle tissue appears normal in echotexture.3
- Ultrasound appearance of IM hematomas vary with age. Acute IM hematomas appear hyperechoic because of transient muscular edema, whereas subacute IM hematomas appear hypoechoic or heterogeneous with mixed echogenicity.1,2
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2. Peetrons P: Ultrasound of muscles. Eur Radiol
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3. Lee JC, Healy J: Sonography of lower limb muscle injury. Am J Roentgenol