A 62–year–old man presented with three weeks of abdominal distension and bilateral pitting edema of the lower extremities. He noted no shortness of breath or chest pain. His urine output was normal, and he noted no other associated symptoms. His sodium level was 129 mmol/L, albumin was 1.1, and prealbumin was 4.6. CT scan of the abdomen revealed a 50 cm hypoattenuating mass at the splenic flexure, significantly narrowing the tranverse colon. Initial biopsies of the mass revealed a high–grade granular cell tumor or sarcoma subsequently read as a CD163 positive histiocytic sarcoma. In anticipation of debulking surgery to relieve colonic obstruction, the patient was placed on total parenteral nutrition (TPN). Despite five days of TPN, his nutritional status, as assessed by prealbumin, did not improve. After several discussions between the hospitalist’s and surgical teams, and with consultation from nutrition, it was decided to take the patient to surgery despite the low prealbumin.
Histocytic sarcomas are aggressive malignant neoplasms accounting for 1% of all non–Hodgkins lymphomas. Prognosis is assessed like other lymphomas, but decidedly worse prognosis is associated with a tumor size greater than 3.5cm. At 50cm in size, this is one of the largest tumors of this kind reported to date. Histological identification of histocytic sarcomas is difficult due to antibody cross–reactivity to receptors originally thought to be specific for the histocyte lineage. CD163, a hemoglobin scavenger receptor protein, positive in our patient’s tumor, is a new and promising marker that may increase specificity for histiocytic–derived neoplasms. Prealbumin is often used as a measurement of a patient’s nutritional status. Poor nutrition is known to result in poorer surgical outcomes: decreased wound healing and increased mortality. Prealbumin, however, is a negative acute phase reactant, and will be lower in patients with chronic inflammatory states such as malignancy. While TPN may increase serum prealbumin in a certain population of surgical candidates, patients with chronic inflammatory disease may have a lower baseline prealbumin, making it more difficult to improve nutritional status as assessed by this number.
While many clinicians and surgeons use the prealbumin as the sole assessment of nutritional status, spuriously low prealbumin values may reflect either nutritional status or an active inflammatory process. Thus, patients in an inflammatory state may be at a significant disadvantage unless a more global assessment that can account for inflammation can be utilized. The Prognostic Inflammatory and Nutritional Index has been used to assess overall health in populations with increased chronic disease states. Alternatively, in patients with known or perceived inflammatory conditions, assessing the C–reactive protein along with the prealbumin may help identify true nutritional assessments, particularly if the CRP level is low or normal with a low prealbumin.