Pulmonary langerhans cell histiocytosis diagnosed in a cervical lymph node: a case report.

BACKGROUND: Pulmonary Langerhans cell histiocytosis (PLCH) is usually confined to the lungs and is therefore an unexpected finding in a cervical lymph node. CASE: A 52-year-old male with a 40-pack-year smoking history presented to our clinic with cough, fever and cervical lymphadenopathy. Chest computed tomography (CT) showed bilateral pulmonary nodules and enlarged mediastinal lymph nodes, worrisome for an infectious or malignant process. Bronchioloalveolar lavage was nondiagnostic. Fine needle aspiration cytology of the enlarged cervical lymph node revealed atypical histiocytoid cells, suspicious for malignancy. Immunohistochemistry revealed CD1a- and S-100-positive Langerhans cells. These findings, along with the patient's extensive smoking history and characteristic radiographic nodules, favored a diagnosis of PLCH with cervical lymph node involvement. The patient was advised to cease smoking, and no therapy was administered. Months later, follow-up chest CT showed spontaneous resolution of the lung nodules. CONCLUSION: The demonstration of Langerhans cells by immunohistochemical staining of CD1a and S-100 on a fine needle aspiration cell block is a useful diagnostic adjunct. In this case, definitive cytology for Langerhans cells in the appropriate clinical and radiologic setting allowed us to arrive at the correct diagnosis of PLCH in a minimally invasive manner.

Interference with hemoglobin A(1C) determination by the hemoglobin variant Shelby.

Hemoglobin variant carrier status was found in a 46-year-old African American man following detection of a falsely elevated hemoglobin A1c (HbA1c) by ionexchange high-performance liquid chromatography (HPLC, VARIANT A1c, Bio-Rad Laboratories, Hercules, CA). Additional analysis of the hemoglobin variant using the Beta Thal Short program (Bio-Rad) revealed an unknown peak with a retention time of 4.84 minutes and a proportion of 26.3%. No mass shift in alpha-globin or beta-globin proteins was observed by mass spectrometry. DNA sequencing revealed a missense mutation in 1 beta-globin allele corresponding to the hemoglobin Shelby trait. The patient was asymptomatic with a normal hemoglobin value of 13.6 g/dL (136 g/L) but had increased target cells on a peripheral blood smear. An alternative method for HbA1c determination using boronate-affinity HPLC provided a value of 3.9% (0.04; reference range, 4.0%-6.9% [0.04-0.07]), more consistent with the patient's recent blood glucose values in the normal range.