Pernicious Anemia: A Rare Case of Vitamin B12 Deficiency With Hyperpigmentation and Pancytopenia.

The clinical mimicry of vitamin B12 deficiency can often delay its recognition and treatment. Pernicious anemia remains among its major clinical causes. We report the case of a 32-year-old male who presented with symptoms of progressive darkened skin, fatigue, general weakness, and neurological symptoms, with examination notable of severe conjunctival pallor and prominent hyperpigmentation of the buccal mucosa, hands, and feet. Investigations revealed pancytopenia with critically low serum vitamin B12. The presence of serum intrinsic factor antibodies confirmed the diagnosis of pernicious anemia. Parenteral vitamin B12 supplementation resulted in rapid hematological improvement and resolution of hyperpigmentation. This case underscores that hyperpigmentation, pancytopenia, and neurological symptoms should prompt a higher index of suspicion for vitamin B12 deficiency to prevent severe hematologic and neurologic complications with closer attention given to follow-up.