Functional imaging of Langerhans cell histiocytosis by (111)In-DTPA-D-Phe(1)-octreotide scintigraphy

Abstract

Background: Langerhans cell histiocytosis is a rare group of diseases of unknown pathogenesis, variable clinical presentation, and behavior. It encompasses highly aggressive, often fatal, and indolent diseases, with a variety of intermediate forms between the two extremes. Localization and monitoring of Langerhans cell histiocytosis deposits are based on the combined use of different imaging modalities, which include magnetic resonance, computed tomography, and nuclear medicine procedures. Somatostatin receptor scintigraphy recently has been used to image immune-mediated diseases with excellent results.

Methods: In this study, the authors have evaluated the potential role of somatostatin receptor scintigraphy by using (111)In-DTPA-D-Phe(1)-octreotide in a series of patients with Langerhans cell histiocytosis. Eight consecutive patients (2 males, 6 females; mean age, 43 years; age range, 29-60 years) with histologically proven Langerhans cell histiocytosis, in various phases of their disease, were imaged 24 hours after intravenous injection of 111-222 MBq of (111)In-DTPA-D-Phe(1)-octreotide, by using total body and spot view images. The objective of the study was to preliminarily evaluate this technique in the evaluation of Langerhans cell histiocytosis.

Results: Most Langerhans cell histiocytosis deposits were clearly documented by somatostatin receptor scintigraphy, independently from the anatomic location (i.e., skeleton, mucosae, soft tissue, etc.). The correlation between conventional imaging modalities and somatostatin receptor scintigraphy results was fairly good, though this was not considered a primary objective of the study.

Conclusions: Among the various imaging modalities for Langerhans cell histiocytosis, somatostatin receptor scintigraphy is unique, because it accurately depicts the active sites of disease and thus can help in monitoring the response to treatment, together with conventional imaging modalities. Further studies are necessary to confirm the diagnostic value of this technique and clarify the biologic significance of the expression of somatostatin receptors in Langerhans cell histiocytosis.