Category: Musculoskeletal Imaging, Region: Lower extremity-Muscular system / Connective tissue / Skin, Plane: Axial
A 70-year-old man presented to our Institution complaining swelling on the left flank and progressive pain rapidly increased over a period of six weeks. No injury or trauma were reported in the recent past medical history. The physical examination documented a swelling of tense - elastic consistency, not fluctuant or pulsatile, with smooth surface extending from the lateral posterior portion of the left thigh to the ipsilateral groin. No motor or sensory neurological disturbance signs were found. There was no palpable thrill and no bruit. There were no problems bending and extending the bust. A clinical suspect of soft tissue sarcoma was considered and appropriately investigated. Laboratory blood tests were within the limits: normal serum chemistries and coagulation studies : PT = 13 s (ref: 11-14.2), INR = 0.96 (ref: 0.85-1.2), PT% = 89 (ref: 70-100), APTT = 30.0 s (ref: 26 - 37.2), hemoglobin level (13,7 g/dl), platelet count 257,000 u/l (ref: 156,000 - 373,000 u/l). Multi Detector Computed Tomography (MDCT) was subsequently performed in order to assess the size and the location of the lesion. The MDCT was performed with 64-row MDCT scanner (Lightspeed VCT; General Electric, USA) and intravenous administration of contrast medium (120 mL, 2.5 mL/s) (Iomeron 350, Bracco, Italy) followed by a saline chaser (40 mL, 2.5 mL/s). The lesion was located in the suprafascial space of superior oblique and gluteus maximus muscles and constituted by multiple contiguous masses with both fluid and solid density. Contrast enhancement was appreciated only in the peripheral capsule, but not within the inner components of the lesion. Furthermore the capsule appeared sharply divided from adjacent muscle planes (Figure 1). In order to better define the structure of the lesion, a Magnetic Resonance Imaging (MRI) examination was planned. The MRI was performed with 1.5 Tesla MRI scanner (Ingenia 1.5 T; Philips, The Netherlands) and intravenous administration of contrast medium (6.5 mL, 1.5 mL/s) (Gadovist 1.0 mmol/ml, Bayer, Germany) followed by a saline chaser (20 mL, 1.5 mL/s). The lesion showed high signal intensity in T1 weighted sequences and low signal intensity in T2 weighted and STIR sequences. Deeper structures had inhomogeneous signal intensity in all baseline sequences (Figure 2 A, B, C). Contrast-enhanced T1-weighted images showed poor enhancement of the capsule and of the deeper portions (Figure 3B). Like CT examination, MRI scans didn’t show any sign of infiltration of the skin and adjacent muscle structures. Based on these findings and the clinical course, we could not rule out the malignant nature of the lesion, so we decided to perform a single stage marginal excision, including the underlying fascia and muscle tissue, after obtaining a signed informed consent. The lesion was 19×12×5 cm in size, encased in a thick capsule, and when this was cut, blood material spilled out. Some solid, necrotic elements were seen extended from the wall to the interior of the lesion. Histologically, the mass appeared as a pseudo-cystic blood-filled lesion characterized by sclerotic fibrous capsule infiltrated by many CD68 positive histiocytes and surrounded by two main types of vessels: small new granulation tissue associated and large pre-existent vessels. The latter appeared fibrotic, sometime occluded and with signs of re-canalization and many siderophages in vessels walls. All these findings were indicative of chronic haemorrhage. There were no postoperative complications, and there was no sign of recurrence at the 8-week follow-up.