Three unusual Pulmonary fibroleiomyomatous hamartomas: cases report and literature review

Abstract BackgroundPulmonary fibroleiomyomatous hamartomas (PFLH) is an extremely rare benign leision, characterized by most patients have no respiratory symptoms and pulmonary nodules is found during rutine chest imaging. It’s completely different from fibrochondrolipoma (ie.chondrogenic pulmonary hamartoma, FCL), Herein, we report three unusual cases of PFLH in a 48-year-old male patient, a 63-year-old male patient and a 63-year-old female patient,respectively and discuss their morphological characteristics and differential diagnoses including fibrochondrolipoma (FCL), pulmonary fibroadenoma (PFA), primary pulmonary leiomyoma (PPL), bronchioloalveolar adenoma (BAA), solitary fibrous tumor (SFT) and pulmonary metastatic leiomyoma (PML) in female patients.Case presentationThree cases showed singler and multiple nodules in the pulmonary parenchyma,the boundary of these nodules was clear. it showed swelling growth and lobulated in larger tumors. it consisted of the mesenchymal rich in spindle cells and the glandular epithelium tissue. the spindle cells form smooth muscle tissue and fibrous tissue, the glandular epithelium with invagination showed glandular ducts or fissures, disorder of composition. Immunohistochemical staining showed Desmin, SMA,H-caldesmon-positive in the all spindle cells; H-caldesmon-positive, SMA-weak positive and desmin-negative in the long spindle cells; TTF-1,CK7 were positive in glandular epithelium and P63,CK5/6 were expressed in basal cells; HMB45,S-100,CD34, ER,PR were negative in all cells. Additionally, Ki-67 VPI was low and less than 1%. The immunohistochemical analysis combined with the morphological results supported the diagnosis of solitary PFLH (SPFLH) or multiple PFLH (M PFLH). There was no recurrence in SPFLH and recurrence in MFLH in the group.ConclusionsPFLH is a rare benign leision .It originated from the small bronchus or smooth muscle cells of vascular wall which implanted into the lung parenchyma and overgrowth into nodules or mass, the messenchymal component of PFLH is the most important for accurate pathological diagnosis, PFLH is easy to be confused with PFA and PPL when there are not enough immune marker such as SMA,desmin, H-caldesmon to mark the mesenchymal components. Therefore, Diagnosis of PFLH mainly depends on pathological examination, females patients have to exclude PML.