We present a 71-year-old male with oral melanoma and mantle cell hyperplasia who was erroneously diagnosed and treated as mantle cell lymphoma. The differential diagnosis of MCL versus mantle cell hyperplasia is a challenging task. Thorough immunohistochemical and cytogenetic analyses are warranted before treatment administration. The more common presentation of amelanotic malignant melanoma requires a high index of suspicion for masses identified in the mouth and requires biopsy for definitive diagnosis. A meticulous physical examination is advocated.