Langerhans Cell Histiocytosis: A Rare Case of Unifocal Gastrointestinal Tract Involvement

Langerhans cell histiocytosis (LCH) is a rare condition caused by the clonal proliferation of bone-marrow-derived antigen-presenting Langerhans cells. Its incidence is prevalent in the pediatric population with 4-5 million cases per year and in adults the incidence is even more rare with approximately 1-2 million cases per year. It can manifest as a unifocal, multifocal single-system, or even multi-system disease, which creates a true medical challenge in its diagnosis and management. LCH most commonly presents with osseous lesions, but is exceedingly rare in the GI tract with the prevalence limited to only a handful of cases–approximately less than 30 in the English literature to date to the best of our knowledge. We present a 44-year-old Caucasian female with a past medical history significant for GERD, type 2 diabetes mellitus, gastroparesis, essential hypertension, and a family history of colon cancer in the patient's maternal and paternal uncles was referred for evaluation of chronic abdominal pain and diarrhea via colonoscopy. Before the procedure, the patient admitted to chronic diarrhea and intermittent but self-resolving left lower quadrant abdominal pain, but otherwise denied any hematochezia, constipation, tenesmus, nausea or vomiting with oral intake, unintentional weight loss, fevers, chills, or recent illnesses. Colonoscopy showed erythema throughout the sigmoid colon, ulceration in the transverse colon, and a single sessile 2 mm polyp was found in the rectum. Transverse colon biopsy revealed a submucosal infiltrate of Langerhans cells with indented nuclei and pale eosinophilic cytoplasm and admixed inflammatory cells. Furthermore, immunohistochemical staining revealed cells strongly positive for S-100 protein, CD-1a, and CD56-confirming Langerhans cell histiocytosis. Due to the scarcity of studies and trials available for both GI and non-GI LCH cases, it is still difficult to arrive at a definitive standardized treatment protocol. In addition, the number of adult cases compared to the pediatric population is sparse and limits the application of novel treatment strategies to more than just the pediatric population. Although our patient had favorable outcomes without florid systemic involvement and continues to do well, follow-up with patients is crucial to rule out progression to systemic disease. Furthermore, future studies and trials will also be paramount in narrowing down the disease pattern of LCH and its predilection for certain presentations such as the GI tract in order to develop targeted and effective treatment strategies in patients with LCH. Our case is another rare presentation that contributes to the understanding of this highly variable disease and possible treatment with further clinical studies and trials.

No relevant conflicts of interest to declare.