Immunocytochemical investigation of Langerin (CD207) is a valuable adjunct in the cytological diagnosis of Langerhans cell histiocytosis of the thyroid.

Langerhans cell histiocytosis (LCH) is an uncommon disease encompassing three clinically different entities: eosinophilic granuloma, Hand-Schüller-Christian disease, and Abt-Letterer-Siewe disease. Despite usually being a multisystemic disease affecting numerous different organs, involvement of the thyroid gland is extremely rare, and only a few cases in adults have been described in the literature. Herein, we present the case of a 28-year-old male patient presenting with LCH involving the skin, the skeletal system, and the thyroid gland. Fine needle aspiration (FNA) of the thyroid was performed and showed the typical Langerhans cells (LC) with foamy cytoplasm and slender nuclei with longitudinal grooves against a background of inflammatory cells with only a few eosinophilic granulocytes. Immunocytochemically, the LC showed positive staining with antibodies against CD1a and Langerin, a recently detected glycoprotein exclusively expressed in LC. Langerin is the major protein that makes up the so-called Birbeck granules, the electronmicroscopical hallmark of LC. Since LCH involvement of the thyroid is occasionally mistaken for papillary thyroid carcinoma cells, we propose that application of Langerin in combination with CD1a is a helpful diagnostic adjunct for the correct assessment of LCH affecting the thyroid gland.

AKT is highly phosphorylated in pheochromocytomas but not in benign adrenocortical tumors.

CONTEXT: Activation of AKT plays a major role in a variety of human neoplasias. In mice, a heterozygous deletion of the Pten gene is associated with increased activation of AKT and with development of pheochromocytomas. OBJECTIVE: The objective of this study was the investigation of the role of AKT in the pathogenesis of pheochromocytomas and adrenocortical tumors. DESIGN, SETTING, AND PARTICIPANTS: Total AKT and phosphorylated AKT (pAKT) in 15 pheochromocytomas, nine aldosterone-producing adenomas, nine cortisol-producing adenomas, eight adrenocortical carcinomas (ACC), and 15 normal adrenals were investigated by Western blot analysis. Immunohistochemistry for total AKT and pAKT was performed in pheochromocytomas (n = 8), ACC (n = 4), and normal adrenal glands (n = 2). In addition, in pheochromocytomas PTEN protein expression and PTEN loss of heterozygosity were analyzed. MAIN OUTCOME MEASURES: Determination of pAKT/total AKT ratio in adrenal tissues was the main outcome. RESULTS: In comparison to normal adrenals, total AKT expression was elevated in both pheochromocytomas (193 +/- 22%) and ACC (176 +/- 36%). The pAKT/AKT ratio was significantly increased in pheochromocytomas (338 +/- 49% vs. 100 +/- 11%) but not in ACC, aldosterone-producing adenomas, and cortisol-producing adenomas. No loss of heterozygosity of PTEN and no decrease in PTEN protein was detected in pheochromocytomas. Immunohistochemistry showed strong and homogeneous AKT and pAKT staining in pheochromocytomas and focal staining in ACC. CONCLUSION: Our findings provide evidence for increased activation of AKT in pheochromocytomas but not in adrenocortical adenomas.