Kenney Barton, Pinto Marguerite, Homer Robert
Department of Pathology, Yale University School of Medicine, 20 York St. EP-2, New Haven, CT 06510, USA.
Diagn Pathol. 2007 Jun 29;2:21. doi: 10.1186/1746-1596-2-21.
The normal visceral and parietal pleura are composed of a mesothelium-lined layer of fibrous connective tissue, consisting predominantly of collagen and elastin fibers, with interspersed nerves, lymphatics, and blood vessels. There is no normal epithelial component to the pleura, and the histologic finding of epithelial cells within pleural tissue typically indicates the presence of a malignant process. The one documented exception to this rule is the occasional occurrence of endometriotic implants, which can result in cyclic thoracic symptomatology and occasionally even hemothorax.
We present a case of seemingly benign epithelial inclusions within the pleura of a sixty year-old male patient who underwent exploratory thoracotomy and subsequent resection of bullous emphysematous blebs. Examination of the surgical specimen revealed well-defined nests of benign-appearing epithelial cells in glandular configurations at multiple sites within the pleura. These cells were immunopositive for TTF-1 and CK7 and immunonegative for calretenin, CK20, and CEA, indicating pulmonary epithelial derivation. Six months after resection, the patient is in stable health, with no clinical or radiologic evidence of bronchogenic carcinoma.
To our knowledge, this is the first report of benign pulmonary epithelial inclusions within pleural tissue. It is important to be aware that benign pleural inclusions occur, so as to avoid confusion with more serious processes in a population of patients who may have oncologic risk factors.
正常的脏层和壁层胸膜由一层衬有间皮的纤维结缔组织组成，主要由胶原纤维和弹性纤维构成，其间散布着神经、淋巴管和血管。胸膜不存在正常的上皮成分，胸膜组织内出现上皮细胞的组织学表现通常提示存在恶性病变。这条规则唯一有文献记载的例外是偶尔出现的子宫内膜异位植入物，它可导致周期性胸痛症状，偶尔甚至引起血胸。
我们报告一例60岁男性患者，其胸膜内存在看似良性的上皮包涵体。该患者接受了开胸探查术，随后切除了大疱性肺气肿性肺大疱。手术标本检查显示，在胸膜内多个部位可见界限清楚的良性上皮细胞巢，呈腺状结构。这些细胞TTF-1和CK7免疫阳性，钙视网膜蛋白、CK20和CEA免疫阴性，提示来源于肺上皮。切除术后6个月，患者健康状况稳定，无支气管肺癌的临床或影像学证据。
据我们所知，这是胸膜组织内良性肺上皮包涵体的首例报告。认识到良性胸膜包涵体的存在很重要，这样可避免在可能有肿瘤危险因素的患者群体中与更严重的病变相混淆。
