Diffuse Large B-cell Lymphoma Presenting as an "Oops" Lesion in the Nasolabial Fold: A Case Report.

We present a case of primary cutaneous diffuse large B-cell lymphoma presented with a small painless nodule in the right nasolabial fold that had persisted for 10 days in a 67-year-old man. Ultrasonographic findings of this lesion mimicked the features of a complicated epidermal inclusion cyst. Primary cutaneous diffuse large B-cell lymphoma was confirmed by an excisional biopsy of the mass Conclusion: The diagnosis of primary cutaneous diffuse large B-cell lymphomas presenting as "oops lesions" in daily clinical practice can be challenging due to their rarity and nonspecific clinical and radiological findings. Therefore, clinical suspicion and awareness are critical for the accurate diagnosis and management of patients with palpable soft tissue masses in the head and neck region.