111In-pentetreotide scintigraphy in patients with Langerhans' cell histiocytosis

Langerhans' cell histiocytosis is a granulomatous disease that may involve multiple organs and the prognosis of which is highly variable. Because the prognosis depends particularly on the number of tissues involved, the accurate identification of the organs involved by granulomatous lesions is of critical importance. We hypothesized that 111In-pentetreotide scintigraphy would be useful for evaluation of patients with Langerhans' cells histiocytosis.

Thirteen patients (38.3+/-10.4 y) with Langerhans' cell histiocytosis (8 patients with unifocal lung disease, 5 with multifocal disease) received intravenous 111In-pentetreotide (111-222 MBq), and planar images were obtained at 24 h after injection. Pulmonary uptake was quantified using a lung-to-background ratio (L/B) and compared with a population of 10 normal scintigrams. For the other sites, uptake of radioactivity in disease-related areas was visually assessed.

Ten of 12 patients with lung involvement had increased lung uptake (UB, 2.23+/-0.49 versus 1.34+/-0.07; P < 0.001). In the patients with multifocal disease, increased 111In-pentetreotide uptake was found in disease-related areas such as the salivary glands, the skin, the soft tissues, and the bones. However, somatostatin receptor imaging was insensitive for detecting central nervous system and liver involvement and most skin lesions.

111In-pentetreotide imaging may be useful in Langerhans' cell histiocytosis. Further study will indicate whether 111In-pentetreotide is a relevant tracer in the management of histiocytosis.