Background. Nasal polyps represent inflammatory non-neoplastic masses of the nasal mucosa that affect 1% to 4% of the general population. They typically occur in individuals older than 20 years, having a higher incidence in males and frequently accompany rhinosinusitis. Case report. We report a case of a 67-year-old woman with a known sleep apnea syndrome, persistent right nasal obstruction, seromucous rhinorrhea, symptomatology with an insidious evolution of about 6 months before the examination. The clinical exam showed a translucent, polypoid appearance, which extended from the level of the right to the left choanal orifice. Gross examination of the surgical specimen revealed a large, firm, white, polypoid mass. Microscopic examination showed large stromal bizarre appearing cells with elongated, hyperchromatic nuclei, surrounded by apparently normal epithelium. In this case, atypical stellate cells scattered throughout myxomatous or edematous stroma can be easily mistaken for a malignant process. Histological changes of spindle shape fibroblasts might be erroneously interpreted as certain pseudosarcomatous changes, low-grade sarcomas, rhabdomyosarcoma, sinonasal myxomas, neurofibroma, and nasopharyngeal angiofibroma. We want to emphasize that the major diagnostic problem could derive from the difficulty of differentiating an allergic or infectious reactive process from mesenchymal or neural origin lesions, due to an extensive proliferation of histiocytes, fibroblasts or irregular myofibroblasts. Another differential diagnosis that could have been considered is a long history of a previously biopsied mass with reactive proliferative stromal cells that can mimic malignancy, represented in our case by the reactive nature of the identified fibroblasts and histiocytes atypia. Conclusions. Although the need for histopathological examination of nasal polyps is controversial, this diagnosis is encouraged, given that there are entities more severe than polyps, requiring examination to avoid a misdiagnosis of mesenchymal malignancy. Rigorous medical history associated with clinical data is important for appropriate patient management.