Patient: Male, 20Final Diagnosis: Anorexia nervosa with gelatinous transformation of bone marrowSymptoms: Bradycardia • generalized weakness • weigh lossMedication: —Clinical Procedure: —Specialty: General and Internal MedicineObjective:Rare diseaseBackground:Anorexia nervosa is a relatively frequently encountered eating disorder. Beyond its psychiatric significance, it is associated with multiple hematological features such as cytopenia. It can be related to gelatinous transformation of the bone marrow.Case Report:We describe the case of a 20-year-old male admitted for rapid involuntarily weight loss. He presented with extreme bradycardia with a heart rate of 30 beats per minute with recent psychomotor impairment. Routine laboratory tests showed pancytopenia, and cytolysis on liver function tests. Cardiac investigations did not reveal abnormalities except for sinus bradycardia. Bone marrow aspirate revealed hypo-cellular marrow with infiltration by gelatinous substance. In addition, bone marrow biopsy showed fat cell atrophy along with loss of hematopoietic elements in areas of gelatinous transformation. During the patient’s hospital stay, he had a restrictive oral diet. Thus, after consulting with a psychiatric specialist, a diagnosis of anorexia nervosa complicated with gelatinous transformation of bone marrow, bradycardia, and acute hepatitis was made. After psychiatric treatment and nutritional care, the patient regained weight, had a normal heart rate and normal liver function tests, and his full blood count and bone marrow examination were within normal range.Conclusions:Gelatinous transformation of bone marrow can be the revealing feature of anorexia nervosa and some potentially reversible associations might prove life threatening if misdiagnosed. Furthermore, lack of suspicion can lead to unwarranted investigations increasing the cost incurred in healthcare delivery. Our patient had 3 systems involved: cardiac, hepatic, and hematological systems. Gelatinous transformation of bone marrow, although a rare condition, must be considered in such patients.