肺罕见良性双相分化性肿瘤——肺腺纤维瘤1例并文献复习

A rare pulmonary benign bi-phasic tumor:a case report of pulmonary adenofibroma and literature review

肺腺纤维瘤(pulmonary adenofibroma)是一种非常罕见的肺原发性上皮与间质双相分化的良性肿瘤,多为胸膜下的实性界清结节,上皮呈简单的腺样结构,偶有乳头或叶状结构,上皮周围围绕着丰富的间质,间质由温和的梭形细胞及胶原组成。在目前有限的病例报道中,尚未发现与肿瘤相关的复发与转移。由于既往报道极少,对此类疾病的认识不足,在冰冻组织病理诊断或穿刺组织病理诊断中,容易将其误诊为恶性病变。本文报道1例肺腺纤维瘤,患者为74岁女性,体检时发现左肺外周型肿物,近年缓慢增大,遂于胸腔镜下行肺叶楔形切除手术。肉眼观肿物呈类圆形,边界清晰,但无明显包膜,切面灰白质韧。显微镜下肿瘤由结构简单的腺样分化的上皮及形态温和的梭形细胞间质两种成分组成,每个间质细胞周围围绕着粗细不一的胶原束,偶见小的粗乳头状或叶状结构。免疫组织化学染色显示腺上皮与肺泡上皮表型一致,间质细胞CD34、B淋巴细胞瘤-2(B-cell lymphoma-2,Bcl-2)、CD99和雌激素受体(estrogen receptor,ER)阳性,S-100、平滑肌肌动蛋白(smooth muscle actin,SMA)以及间皮标记等均为阴性。短期随访患者无复发或转移表现。本文回顾了国内外已报道的相关病例,并对肺腺纤维瘤可能的组织学起源进行初步探讨。

Pulmonary adenofibroma is an extremely rare benign primary tumor of the lung,with characteristic bi-phasic differential pattern. They are usually sub-pleural solid pulmonary nodules with clear margins. The tumor is composed of glands and peri-gland stroma. The glands are often quite simple,forming long and narrow tubules,with uniformly monolayer lining cells. Combined papillary or phyllodes structures were reported in some cases. The stromal cells are spindle-shaped and look mild,mixed with the collagen bands. Up till now,only a few cases of pulmonary adenofibroma have been reported all over the world. And because of the limited recognition,this tumor is easily misinterpreted as malignancy in frozen section or biopsy specimens. We reported a new case of pulmonary adenofibroma. The mass peripherally located in the left lobe of the lung,found by chance in a 74-year-old woman. The patient underwent a wedge resection of the left lung by the thoracoscope,because of the slowly gradual enlargement of the mass annually. An oval grayish-white nodule was sub-pleural located in the specimen,with solid and rubbery texture,but without a distinct capsule. Two distinct components of simple glands and mild spindle cell stroma were found to mix together uniformly under the microscope. Collagen bands of various widths evenly surrounded each stromal cell. A few small coarse papillae or phyllodes structures were randomly distributed in some area. The immunohistochemical staining pattern of the glandular cells was accordant with typeⅡalveolar epithelium. Stromal cells were positive with CD34,B-cell lymphoma-2（ Bcl-2）,CD99 and estrogen receptor（ ER）,while S-100,smooth muscle actin（ SMA） and all the mesothelium markers were negative. The patient was disease free after the surgery,although the follow-up time was only one year. Besides the new case above,we also reviewed all the reported cases,and tentatively discussed the probable histological origin of pulmonary adenofibroma.