Giant pulmonary sclerosing pneumocytoma with potentially malignant biological behavior: a case report and literature review

Abstract

Background Pulmonary sclerosing pneumocytoma (PSP) is a rare benign lung tumor which generally presents as a solitary pulmonary nodule in middle-aged females. However, the PSP in some patients exhibits potentially malignant biological behavior, with recurrence and lymphatic or distant metastasis being observed. Case Description We encountered a case of a 46-year-old female with an inordinately massive tumor 9.5 cm in diameter and a relatively high Ki-67 proliferation rate. Fine needle aspiration (FNA) played a significant but limited role in the preoperative diagnosis: the computed tomography (CT)-guided lung puncture biopsy was consistent with the typical pathology of PSP; however, endobronchial ultrasound-guided transbronchial lung biopsy (EBUS-TBLB) could not provide a definitive diagnosis. The patient ultimately underwent thoracoscopic resection and mediastinal lymph node dissection. Here, we provide a review of the literature on patients with PSP with malignant biological behavior to raise awareness of the malignant potential of PSP and describe our experience to inform future management. Conclusions PSP lacks specificity in its clinical and radiological characteristics and has complex pathological manifestations. FNA is valuable in the diagnosis and differential diagnosis of PSP but involves the risk of misdiagnosis or missed diagnosis. Additionally, we believe that the accepted benign features of PSP need to be updated and that the potential malignant features of PSP should be carefully monitored. Surgical resection is curative but strict follow-up is crucial.

Revisiting Pulmonary Sclerosing Pneumocytoma

“…Cases with multiple nodules, however, even bilateral, have also been reported [ 10 , 11 , 12 , 13 ]. Most of the reported cases show a benign clinical course, but aggressive examples, including cases with distant metastases, also occur [ 4 , 5 , 6 , 14 , 15 , 16 , 17 ]. Wang et al [ 5 ] have detected significant differences in gender, age, and tumor size in PSP with and without metastases.…”

“…For example, Teng et al [ 51 ] have reported the malignant transformation of both surface and stromal cells in a PSP with multiple lymph node metastases. Zhang et al [ 14 ] report a PSP measuring 8.9 cm in diameter containing fibrosclerotic areas and hypothesize that the development of tumor metastases might be associated with stromal overgrowth. Actually, a retrospective study has shown that up to 20% of PSPs with dense stromal overgrowth presented lymph node metastases [ 4 ].…”

“…This tumor usually presents as a solitary nodule sometimes mimicking pulmonary carcinoma [ 9 ]; however, multiple PSPs have also been reported [ 10 , 11 , 12 , 13 ]. Although traditionally considered a benign tumor, some recent series have detected malignant features at least in a subset of cases [ 14 ], including sarcomatoid dedifferentiation [ 6 ], local recurrence [ 15 , 16 ], and metastatic seed [ 4 , 5 , 17 ]. Interestingly, a relevant number of these tumors are coincidental with pulmonary neuroendocrine-related tumors [ 10 , 12 , 18 , 19 , 20 , 21 , 22 , 23 ], although the probable pathogenic links connecting these two conditions still remain under discussion.…”