A twenty-nine-year-old woman was referred to the office for evaluation of an enlarging painful mass in the right calf. The mass, which had first appeared three months previously, was insidious in onset and was not associated with any preceding trauma. It had been previously diagnosed elsewhere as a hematoma on the basis of magnetic resonance images, but concerns were raised when subsequent studies showed that the size of the mass had increased. The pain had worsened two weeks prior to our evaluation, and the patient required a cane to walk. She had no resting or nocturnal pain, constitutional symptoms, or numbness or weakness in the limb, but she did have occasional calf spasms. Her medical history included a cesarean section nine months previously and use of oral contraceptives.
On clinical examination, the patient was a healthy-appearing woman who was in mild discomfort. There was tender, diffuse swelling over the proximal aspect of the right leg. There was no increased warmth, erythema, or overlying skin changes. The Homans sign was absent, and the leg was not tender to percussion. The mass was noncompressible and did not change with limb elevation. The knee was stable during active functional range of motion but painful during the terminal phase of extension of the knee. There was no inguinal or popliteal lymphadenopathy, and the distal neurovascular examination revealed normal findings.
Radiographs showed a soft-tissue density, without mineralization or osseous involvement, in the proximal part of the leg. Magnetic resonance images revealed a 15.0 × 7.4 × 5.8-cm mass in the soleus muscle with a complex heterogeneous internal signal (Figs. 1-A, 1-B, and 1-C). A biopsy was obtained with a 14-gauge Temno needle (Allegiance Healthcare, McGraw Park, Illinois), and the specimen was interpreted as a high-grade undifferentiated sarcoma. A computed tomography scan of the chest, abdomen, and pelvis for metastatic disease and the results of laboratory studies were unremarkable. A transthoracic echocardiogram was interpreted as normal. The patient subsequently received neoadjuvant chemotherapy that included two cycles of Adriamycin (doxorubicin hydrochloride) and ifosfamide followed by a wide local excision of the mass and placement of brachytherapy catheters in the tumor bed.
The gross specimen was 14.0 × 12.5 × 7.0-cm in size and had a well-formed pseudocapsule. The tumor was composed of a pleomorphic cell population that had a high mitotic rate (more than ten typical and highly atypical mitoses per high-power field at ×400 magnification) and was associated with 60% necrosis. The tumor cells were epithelioid, with vesiculated and clear cytoplasm with no obvious intercellular connections, mucin production, or pigment production. Immunohistochemistry showed positivity for vimentin (a ubiquitous marker used to test antigen preservation) and focal positivity for S-100 protein (a melanoma, neural, and adipose marker) and cytokeratin (an epithelial marker). HMB45 (melanoma), CD31 and CD34 (endothelium), desmin (muscle), and smooth muscle actin (SMA) (smooth muscle) markers were negative. A diagnosis of high-grade undifferentiated pleomorphic sarcoma was made. The margins of resection were negative. The postoperative course was uneventful, and the patient received a total dose of 34 Gy of brachytherapy in ten fractions over a period of five days (radiobiologically equivalent to a total dose of 60 Gy given once daily for six weeks). No external beam boost was recommended, and brachytherapy was the sole modality of radiation delivery that was used.
The patient was well for the next three months but then presented with an acute, painful, pale, and pulseless contralateral left lower extremity with associated tachycardia and tachypnea. A thromboembolism of the left femoral artery was found along with a transthoracic echocardiographic finding of a 5.0-cm mass involving the posterior mitral valve leaflet. An emergent femoral thrombectomy was performed, and perfusion to the limb was restored. The cultures did not demonstrate growth of any organism, and histologic analysis revealed blood clots with no malignant cells. The patient was afebrile and blood cultures were negative, although the total leukocyte count was elevated to 25,000/mm3 (25 × 109/L). Given her history, a metastatic cardiac mass was favored over subacute bacterial endocarditis as a cause of this thromboembolus. A repeat metastatic workup did not reveal any other site of metastatic disease or recurrence in the calf. A transesophageal echocardiogram demonstrated a large pericardial effusion and a large mass bivalving through the mitral outflow tract, creating concerns over a possible acute obstruction (Figs. 2-A and 2-B). Cardiac exploration revealed a tense pericardial effusion containing a large amount of serous fluid, which was drained and found to be negative for malignant cells on histologic analysis. There was a 5.0 × 2.0 × 1.5-cm mass that invaded the posterior part of the left ventricular wall and extended anteriorly through the posterior part of the mitral anulus, destroying the posterior mitral leaflet, with the bulk of the mass bulging into the left atrium. A frozen section of this mass was interpreted as a high-grade undifferentiated sarcoma. Also noted was a 0.5 × 0.5-cm primary atrioseptal secundum defect with a back-bleeding of dark venous blood from the right atrium. This defect was primarily repaired, controlling the bleeding. The bulk of the tumor was excised with the posterior part of the mitral valve and the chordae, which were all transected down to the papillary muscles. The tumor was growing through the papillary muscles of the anterior leaflet, although the anterior leaflet itself was not involved. The tumor in the posterior part of the left ventricular wall could not be entirely resected due to its precarious location and the fact that this was a metastasis with a grave prognosis. The defect in the posterior part of the anulus was repaired with use of a pericardial patch. The mitral valve was replaced with a 27-mm Mosaic mitral bioprosthesis, Model 310 (Medtronic, Minneapolis, Minnesota). The histopathology was consistent with a high-grade undifferentiated pleomorphic sarcoma, similar to the previously excised calf mass (Figs. 3-A and 3-B). A diagnosis of a solitary cardiac metastasis was made. The mass recurred within three weeks, presenting as congestive heart failure. Metastasis to the brain occurred shortly thereafter, and the patient died of an intracerebral hemorrhage four weeks after cardiac surgery.