Cytological diagnosis of Langerhans cell histiocytosis: A series of 47 cases

Abstract

Objective Langerhans cell histiocytosis (LCH) is a rare disease affecting predominantly children and young adults but can be found in any age group. Diagnosis of LCH is often difficult and can be delayed because of its rarity. The present study highlights the cytomorphological features in a large cohort of cases. An accurate cytological diagnosis may avoid unnecessary biopsy and guide appropriate management. Method Fourty seven (47) cases of LCH diagnosed on cytological material & fine-needle aspiration (FNA) over a period of 14 years (2003-2016) were retrieved from the archives. The cytological smears were evaluated and microscopic findings collected by semi-quantitative assessment done by two different pathologists Result The age at the diagnosis of the patients ranged from 9 months to 28 years. The majority of cases were in the age group of 0-5 years. The most common site was head and neck region, which included cervical lymphadenopathy and scalp swelling. Two cases were diagnosed each from inguinal lymph node and bronchio-alveolar lavage (BAL). Cytological smears in the majority of the cases were moderate to highly cellular (58%) and showing abundant Langerhans cell in (72%) of cases. Areas of necrosis were seen in 38%, while 78% of cases showed giant cells. The majority of cases showed mild eosinophilia (61%), sparse lymphocytosis (83%) and mild neutrophilic infiltration (64%). There were 1-2 mitoses per 10 high power field in 12 cases (25.5%). No abnormal mitoses were identified. Conclusion The presence of cells with features of Langerhans cells associated with the expression of selected immunohistochemical markers allow the diagnosis of LCH on cytological samples, sparing more invasive procedure as a biopsy.