Sinonasal non Hodgkin lymphoma (NHL) is a very rare condition.

NHL located specifically in the frontal sinus is even rarer with only 15 cases in the literature reported to date.

A unique case of diffuse large B-cell lymphoma of the frontal sinus that presented first and was treated as suspected Potts puffy tumor is presented.

A 69-year-old white man with a history of sinusitis and two recent endoscopic sinus surgeries presented with enlargement of his right forehead. Computed tomography and magnetic resonance images revealed a dense opacification of the frontal sinus bilaterally, thickening and enhancement of the dura mater behind the right frontal sinus, and local osteomyelitis-like lytic bone changes. A bifrontal craniotomy was performed. Radical exoneration of the frontal sinus, copious antibiotic-impregnated irrigation after culture swabs, and resection of presumed granulation tissue was performed. Culture swabs remained negative, but histopathology revealed diffuse large B-cell lymphoma. Subsequent chemotherapy was administered.

Sinonasal NHL is very rare but can occur in the frontal sinus and may present as a suspected Potts puffy tumor. A high clinical suspicion is necessary for early diagnosis and treatment ¹⁾.