O. Angoue

18F-fluoride PET/CT aspect of an unusual case of Erdheim-Chester disease with histologic features of Langerhans cell histiocytosis.

We report the case of a 63-year-old woman with Erdheim-Chester disease (ECD) and histologic features of Langerhans cell histiocytosis, both extremely rare histiocytic proliferations responsible of skeletal and extraskeletal involvement. 18F-Fluoride PET/CT revealed multiple intense focal uptake scattered throughout the skeleton. We also performed an 18F-FDG PET/CT which point out visceral and vascular involvement. This case illustrates the interest of PET/CT in ECD, a rare polymorphus and systemic disease, and in our knowledge, this is the first reported illustration of 18F-fluoride PET/CT findings in this pathology.

Granulosa cell tumor of the ovary with high FDG uptake.

Granulosa cell tumor (GCT) of the ovary is a rare tumor accounting for 2%-5% of ovarian malignancies. Although the usefulness of 18F-FDG PET/CT is well demonstrated in the staging and follow-up of the great majority of ovarian cancers, GCTs are known to cause false-negative results on FDG PET because of very low FDG avidity. We present a case of a GCT in which an 18F-FDG PET/CT proved very useful in the detection of recurrence.

Assessment of microcirculatory effects of glycine by intravital microscopy in rats

Experimental studies using laboratory animal models have shown a potential vasoactive effect of natural metabolites such as glycine. The present study used intravital microscopy in laboratory rat models to study the microcirculation in the brain pial and mesentery vessels. To investigate the pial microvasculature, a stereotaxis-like animal fixing device was used. The intravital microscopy unit consisted of a binocular microscope equipped with a digital photo-video camera, processor, monitor and printer. Using reflected light, a special contact lens with an amplified focus depth provided high-resolution images of nontransparent tissue objects that typically have insufficient light exposure. Glycine had a vasodilatory effect on microvessels in the rat brain and mesenterium. The diameter of pial arterioles increased after glycine application especially markedly (up to 250% of initial size). These changes were not observed when physiological saline was used. Even a very small amount of glycine (a drop on the needle) was sufficient to stop the early stages of histamine-induced blood stasis development in 3-5 s in mesenterial microvessels. The vasodilatory effect of glycine on the pial microcirculation correlates with its reported positive therapeutic effect in cerebral ischemic stroke. The ability of glycine to avoid or prevent histamine-induced microcirculatory alterations in mesenterial microvessels may have potential clinical applications.

Bone scintigraphy pattern of joint chronic graft-versus-host disease after allogeneic bone marrow transplantation.

A 38-year-old man presented with an inflammatory polysynovitis involving the knees, ankles, hands, and shoulders, which appeared 1 year after bone marrow transplantation for chronic myeloid leukemia worsening. The diagnostic considerations included incipient iatrogenic or autoimmune inflammatory rheumatism, joint leukemia relapse, osteoarthritis, and joint chronic graft-versus-host disease (cGVHD). MRI appeared to be osteomyelitis. Radionuclide imaging suggested joint cGVHD diagnosis, which was confirmed by pathologic and microbiological studies, disclosing osteonecrosis but no rheumatoid, oncological, or infectious pattern. One-year follow-up showed clinical improvement under infliximab therapy and confirmed the diagnosis of joint cGVHD.