To the Editor:
We have seen an 82-year-old woman with pulmonary sclerosing pneumocytoma (PSP) presenting as a lesion suspicious of malignancy. We consider that is a valuable observation as PSP is a rare benign disorder that presents a diagnostic and therapeutic challenge.
An overall healthy 82-year-old-woman presented with cough and mild dyspnea. Chest computed tomographic scan showed a well-defined, smooth bordered pulmonary nodule in the right lower lobe (Fig. 1), which had been slowly increasing in size over 10 years (from 3.7 mm to 2.2 cm). The patient underwent flexible bronchoscopy and the nodule was sample under direct ultrasound visualization. There were no suspicious mediastinal or hilar lymph node stations identified.
Cytologic evaluation of the moderately cellular aspirate showed a bland biphasic population of cells, including surface epithelial cells with focal papillary architecture along with solid sheets of round to polygonal cells, present in a hemorrhagic background with hemosiderin deposition (Fig. 2). Both cell populations stained positive for TTF-1 and variably with cytokeratin cocktail, but were negative for p40 and the neuroendocrine markers synaptophysin and chromogranin. Given this findings, a diagnosis of PSP was made. The clinical, radiographic, and pathologic findings were discussed at a multidisciplinary conference with Pulmonology, Radiology, Thoracic Surgery, and Oncology. The decision was made to monitor the lesion with periodic imaging.
PSPs originate from undifferentiated respiratory epithelium. On gross examination, they are well-circumscribed yellow-tan masses typically located in the lung periphery. The differential diagnosis of PSP included a well-differentiated lung adenocarcinoma, pulmonary carcinoids, and metastatic papillary thyroid carcinoma.1 Immunohistochemistry staining is typically needed to differentiate between PSPs and other tumors, primarily adenocarcinoma, and carcinoid.2
Given the low prevalence, little is known about the clinical management of PSP. Clinically, most patients are middle-aged women and lesions are identified incidentally. Although patients are commonly asymptomatic, hemoptysis has been reported as the most common clinical manifestation in up to 7.9% of patients, whereas other symptoms are nonspecific respirator complaints such as cough and chest pain. On radiographic evaluation, PSPs are oval or round with smooth boundaries. As PSPs typically present as a solitary pulmonary nodule on chest computed tomography, they can be easily confused with primary lung cancer (21.2%), metastatic disease (15.8%), or hamartomas (14.4%).3
It is important to mention that while PSPs are a benign lesion, they can be present with a concomitant malignancy. Cases of associated breast and thyroid cancer, neuroendocrine carcinoma, and adenomatous hyperplasias have been reported. We want to emphasize that heightened clinical suspicion should be maintained given their radiographic appearance and association with other malignancies.3
Pneumocytomas typically have an indolent and benign course. However, therapeutic approaches have varied. In a case series of 28 patients, enucleation was the most common procedure performed while patients with central tumors underwent lobectomy.4 In patients with nonresectable PSP due to anatomic considerations, external beam radiation therapy has been proposed as an alternative treatment strategy.5
The reason for this letter was to highlight the importance of multidisciplinary approach in the management of these lesions. PSP is a rare entity that is often mistakenly diagnosed as adenocarcinoma on cytology. This leads to potential overtreatment (ie, lobectomy, radiation therapy) emphasizing the need to combine radiologic, clinical, and pathologic findings upon diagnoses.
Estefania Rivera, MD*
Yaron Gesthalter, MD†
Paul VanderLaan, MD*
Mihir S. Parikh, MD* *Division of Thoracic Surgery and Interventional Pulmonology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA †Department of Interventional Pulmonary Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco (UCSF) San Francisco, CA
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2. Ng WK, Fu KH, Wang E, et al. Sclerosing hemangioma of lung: a close cytologic mimicker of pulmonary adenocarcinoma. Diagn Cytopathol. 2001;25:316–320.
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