Introduction Alveolar adenoma belongs to the group of benign epithelial tumors. Histogenesis of alveolar adenoma is a combination of proliferation of alveolar pneumocytes and fibrous tissue originating from septal mesenchyma. Case outline A sixty-nine-year old female patient was hospitalized for clinical examination and surgery of well defined and homogenous timorous lesion in the right middle lobe causing pleural pain. Bronchoscopic examination with biopsy did not resolve etiology of the disease. Tumorectomy was performed. Timorous nodule had a multicystic appearance and histologically, histochemically and immunohistochemically, an alveolar adenoma was estimated. Five years after surgery, the patient feels well, without respiratory symptoms and signs of recurrence or malignant alteration, respectively. Conclusion Alveolar adenoma is a rare benign lung tumor, most frequently presented as a solitary pulmonary nodule. After complete surgery, the tumor neither relapses nor malignantly alters. Surgical excision is curative. It is necessary to take into consideration alveolar adenoma, too, when a solitary pulmonary nodule is diagnosed.
