Differential Diagnosis for a 22-year-old with Granulomatous Lymph Nodes and Gastric Ulcer

Single most likely diagnosis

• Crohn's Disease: This condition is a type of inflammatory bowel disease (IBD) that can cause gastric ulcers and granulomatous lymph nodes due to its systemic inflammatory nature. The absence of evidence for sarcoidosis, lymphoma, and tuberculosis, combined with the presence of gastric ulcers, makes Crohn's disease a strong consideration.

Other Likely diagnoses

• Wegener's Granulomatosis (Granulomatosis with Polyangiitis, GPA): This is a form of vasculitis that can affect various parts of the body, including the gastrointestinal tract, and can cause granulomatous inflammation. Although less common, it's a plausible diagnosis given the symptoms.
• Eosinophilic Gastroenteritis: This condition involves eosinophilic infiltration of the gastrointestinal tract, which can lead to gastric ulcers and systemic symptoms, including lymphadenopathy. It's less common but should be considered in the differential diagnosis.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

• Lymphoma (especially if initial workup was not exhaustive): Although the initial workup showed no evidence of lymphoma, this diagnosis can sometimes be elusive, requiring multiple biopsies or more sensitive tests. Missing a lymphoma diagnosis could have severe consequences.
• Tuberculosis (if the workup was not comprehensive): Similar to lymphoma, tuberculosis can be difficult to diagnose, especially in its extrapulmonary forms. A thorough investigation, including cultures and molecular tests, is crucial to rule out TB.
• Sarcoidosis (if the initial evaluation was incomplete): Sarcoidosis can manifest in various ways, including gastrointestinal involvement and lymphadenopathy. It's essential to ensure that the initial workup was comprehensive enough to rule out this condition.

Rare diagnoses

• Whipple's Disease: A rare, systemic bacterial infection caused by Tropheryma whipplei, which can lead to malabsorption, weight loss, and lymphadenopathy. It's a diagnosis of exclusion but should be considered in puzzling cases.
• Histoplasmosis or other fungal infections: In endemic areas, histoplasmosis can cause granulomatous lymphadenitis and gastrointestinal symptoms. Although rare, it's an important consideration in the right geographic and clinical context.
• Castleman Disease: A rare disorder that involves an overgrowth of cells in the body's lymph nodes, which can cause a variety of symptoms including lymphadenopathy and systemic inflammation.