Procalcitonin Perplexity - Prolonged Idiopathic Elevation in Pleomorphic Sarcoma: A Case Report and Review of the Literature

Historically, elevations in procalcitonin (PCT) have been implicated in medullary thyroid cancer and neuroendocrine tumors. More recently, the trending of PCT has been suggested as a monitor of infection to assess the presence, clearance and eradication of infection, especially in cancer patients. Its increase serves as a marker of bacterial infections. During homeostasis it is produced by most tissues in the body at an extremely low level (<.01 ng/mL) and is often induced by bacterial endotoxins. In cancer patients additional factors influence these levels. Metastasis in particular is linked with relatively higher PCT levels. We present a case of an afebrile patient with undifferentiated pleomorphic sarcoma who underwent 25 cycles of radiation therapy and presented one month later with elevated procalcitonin, lactic acid, and leukocytosis. All infectious work up was negative. Findings were incidental after a hospital visit for dehydration. Leukocytosis and lactic acidosis resolved after four days into the hospitalization. Procalcitonin, however, remained elevated over four months in the range of 2-5 ng/mL. The patient has no findings of metastatic disease. To our knowledge, there has never been a report in the literature describing a prolonged elevation of procalcitonin in a patient with a non-metastatic sarcoma without any signs of infection or any other underlying cause. The elevation of PCT has been noted in patients who suffered burns, trauma, minor and major surgery, and cardiogenic shock in addition to infection. Increases have served as signs of worsening patient outcomes and elevated rate of complications. Trending PCT can help in appropriated antibiotic use as it has been shown to decrease antibiotic use by 2.4 days. PCT trends have been increasing in value making idiopathic elevations found in combination undifferentiated pleomorphic sarcoma an important addition to the literature.

Keywords: antibiotic administration; antibiotic stewardship; cancer; infection; infectious disease; oncology; pleomorphic sarcoma; procalcitonin; sepsis.