Undifferentiated Epithelioid Sarcoma Presenting as a Fever of Unknown Origin

A Case Report

Nicholas Sajko; Shannon Murphy; Allen Tran


J Med Case Reports. 2019;13(24) 

In This Article

Case Presentation

A 73-year-old Caucasian woman with a medical history significant only for hypertension, presented to our emergency department complaining of intermittent subjective fever, anorexia, weakness, and fatigue for 2 weeks. Her subjective fevers were occurring almost nightly, and she had associated night sweats. Her weight was stable. She had a persistent non-productive cough. There was no sore throat or rashes. Her review of systems was negative for any other current symptoms. Her only medication was enalapril. Her family history was non-contributory.

She had been previously assessed by her family doctor for the same symptoms 2 weeks prior to this presentation. Routine investigations were unrevealing. At that time, she had left knee pain that developed after a hike the previous month. X-rays of her knee and femur were unremarkable. Her pain resolved within a week. No therapeutic interventions were undertaken at that time.

She had no sick contacts, no sexual partners, and no insect or tick bites. She had no known exposure to tuberculosis. She travelled to the Channel Islands 3 months before presentation. She had no animal exposures. She denied any history of injection drug use.

On initial examination, she appeared non-toxic. Her vital signs included a temperature of 38.6 °C, a heart rate of 96 beats/minute, blood pressure of 130/65 mmHg, and oxygen saturation of 99% on room air. There were no rashes and no lymphadenopathy was present. There were no signs of hyperthyroidism and the thyroid itself was normal in size without any nodules. Her jugular venous pulse was 2 cm above the sternal angle. She had normal heart sounds with no extra sounds or murmurs. There were no stigmata of endocarditis. Her lungs were clear with equal breath sounds bilaterally. An abdominal examination revealed a soft and non-tender abdomen. There was no hepatosplenomegaly, jaundice, or asterixis. Examination of her knees did not reveal any redness, warmth, effusions, or pain. A screening neurologic examination demonstrated grossly normal cranial nerves, full strength bilaterally, and normal reflexes, tone, and coordination. She was admitted for further investigation for her fever of unclear cause. Empiric piperacillin-tazobactam and intravenously administered saline were started on admission as acute bacterial infection was in the differential diagnosis.

Table 4 displays the results of her laboratory investigations. A peripheral smear was unremarkable. Serum free light chains were normal. No monoclone was found on serum protein electrophoresis. Urine analysis was bland. Five sets of blood cultures, a urine culture, and Lyme serology were negative. A chest X-ray was normal. Computed tomography (CT) scans of her head, neck, chest, abdomen, and pelvis were all unremarkable. A transthoracic echocardiogram revealed a normal heart with no vegetations.

She had one further temperature of 39.4 °C while in hospital, without any clear infectious source. Once the blood cultures were known to be negative, piperacillin-tazobactam was stopped. There was an impression that her workup could be continued on an out-patient basis as immediately life-threatening causes of fever had been ruled out. She was discharged home after an 8-day admission in hospital with plan for out-patient follow up.

She was seen 1 month after discharge. She had no improvement in her symptoms and noted a recurrence of her left leg pain. Her C-reactive protein (CRP) was 207 mg/L. On examination, she had a large, warm, left thigh mass. An urgent ultrasound revealed a 4.5 × 6.8 × 11.6 cm spindle-shaped, well-defined soft tissue mass with internal vascularity (Figure 1). Magnetic resonance imaging (MRI) found that the mass met the femur but was not invading (Figure 2). An initial biopsy revealed a poorly differentiated malignant neoplasm.

Figure 1.

Ultrasound imaging of left thigh mass. Mass outlined with dashed white line

Figure 2.

Magnetic resonance imaging investigation of left thigh mass. a Coronal magnetic resonance image of thighs. b Cross-sectional image of left thigh

She underwent a distal femur excision with distal Global Modular Replacement System (GMRS) reconstruction. Final pathology revealed a grade 3, pT2bN0M0 undifferentiated sarcoma with epithelioid morphology. She had no nodal involvement or distant metastases at this time. Her CRP fell to 28.42 mg/L within 8 days of surgical excision. She recovered well from her surgery with resolution of her constitutional symptoms. She subsequently was planned to receive radiation therapy.

Prior to receiving radiation therapy, a follow-up CT scan was done a couple months after her surgery. This revealed the presence of a new 4 mm pulmonary nodule in the lower lobe of her left lung that was not felt to be a metastasis. There was no other evidence of distant metastases. Given these results, adjuvant radiation treatment was begun. She received 6600 cGy given in 33 fractions to her leg.

Roughly 1 month following the end of her radiation therapy course, she re-presented to our emergency room with painless hematuria and a month-long history of non-productive cough associated with decreased energy. CT scans of her chest revealed 16 pulmonary masses, measuring up to 6.2 cm. A CT scan of her abdomen and pelvis revealed a solitary nonobstructive renal calculus, as well as a new 3.2 × 6.5 cm pelvic mass.

She was subsequently referred to radiation and medical oncology where a shared decision was made to pursue palliative management.

Figure 3 provides a timeline of the above described case.

Figure 3.

Case report timeline of events. BP blood pressure, bpm beats per minute, CRP C-reactive protein, CT computed tomography, ED emergency department, HR heart rate, MRI magnetic resonance imaging, RA room air, Sat saturation, T temperature