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Pulmonary, Critical Care, and Sleep Pearls |

A 33-Year-Old Woman With a Fluorodeoxyglucose-Avid Left Lower Lobe Mass FREE TO VIEW

Sujith V. Cherian, MD; Rosa M. Estrada -Y- Martin, MD, FCCP; Adel D. Irani, MD; Jain Zhou, MD, PhD; Annikka Weissferdt, MD
Author and Funding Information

aDivisions of Pulmonary, Critical Care and Sleep Medicine, University of Texas Health- McGovern Medical School, Houston, TX

bDepartment of Cardiothoracic and Vascular Surgery, University of Texas Health- McGovern Medical School, Houston, TX

cDepartment of Pathology and Laboratory Medicine, University of Texas Health- McGovern Medical School, Houston, TX

dDepartment of Pathology, The University of Texas- MD Anderson Cancer Center, Houston, TX

CORRESPONDENCE TO: Sujith V. Cherian, MD, Divisions of Pulmonary, Critical Care and Sleep Medicine, University of Texas Health- McGovern Medical School, 6431 Fannin St, Houston, TX 77030


Copyright 2016, American College of Chest Physicians. All Rights Reserved.


Chest. 2017;151(5):e119-e122. doi:10.1016/j.chest.2016.10.049
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Published online

A 33-year-old woman of Latin American origin was referred to our department by her primary care physician for a left lower lobe mass, which was incidentally found on a CT scan of her abdomen. The patient had complaints of abdominal pain for which she underwent imaging of her abdomen. Review of systems was negative for any respiratory complaints, and she denied any history of cigarette smoking or recreational drug use.

Figures in this Article

Vital signs were BP 120/70 mm Hg, pulse rate 90 beats per minute, respiratory rate 14 breaths per minute, and oxygen saturation 98% on room air. She was afebrile and was not in acute respiratory distress. Physical examination was significant only for decreased respiratory sounds in the left lung base.

Complete blood count and complete metabolic panel were completely normal. Chest CT scan revealed a 5- × 5.3- × 5.3-cm mass abutting the pleura and chest wall. This was followed by a PET scan, which showed the mass with a maximum standardized uptake value (SUV) of 6.4 (Figs 1A, 1B). Pathology of CT-guided biopsy of the mass was initially read as well-differentiated adenocarcinoma of the lung, based on immunostain positivity with Thyroid transcription factor (TTF-1), Napsin A, and Cytokeratin 7. Further staging workup was negative for mediastinal or extrathoracic involvement; subsequently, she underwent a left lower lobectomy.

Figure 1
Figure Jump LinkFigure 1 A, Chest CT scan mediastinal window showing left lobulated lung mass abutting the left pleura and chest wall. B, PET scan demonstrating 18 F-fluorodeoxyglucose-avid left lower lobe mass.Grahic Jump Location

What benign tumor could account for the imaging studies and immunostain results?

Diagnosis: Sclerosing hemangioma of the lung.

Sclerosing hemangioma (SH) of the lung, first described by Liebow and Hubell, is an uncommon and benign lung tumor, which is believed to derive from incompletely differentiated respiratory epithelium. The highest incidence of this benign tumor is in middle-aged Asian women. Although initially thought to be of vascular origin, immunohistochemical studies strongly suggest that it originates from primitive respiratory epithelium (type II pneumocytes), and it is sometimes referred to as pneumocytoma.

SH reflects two common histologic features of these lesions: sclerosis and ectatic vascular spaces. Currently, these features are considered secondary changes in what is regarded as an epithelial neoplasm. These tumors consist of two epithelial cell types, surface cells and round cells, and four architectural patterns, papillary, sclerotic, solid, and hemorrhagic. Surface cells are cuboidal and resemble reactive type II pneumocytes, hence the name pneumocytoma, whereas round cells are small with well-defined borders, fine chromatin, and inconspicuous nucleoli. Of SHs, 95% display three architectural patterns, most commonly papillary, sclerotic and solid, which give SH its hallmark histologic heterogeneity. Several immunohistochemical studies have demonstrated that both surface and round cells exhibit nuclear expression of TTF-1 and membranous/cytoplasmic expression of epithelial membrane antigen in nearly all cases. In addition, surface cells show positivity for pancytokeratin (AE1/AE3) and surfactant proteins, all of which point to primitive respiratory epithelium origin. Based on the increased incidence of SHs in women, sex hormone receptor expression has been studied with some cases showing progesterone and estrogen receptor expression, suggesting a relationship between this tumor and female sex hormones.

SH typically occurs in middle-aged adults (mean age, 46 years), with a female to male ratio of 5:1, with a higher incidence in Asia. The most common presenting form is an asymptomatic solitary pulmonary nodule or mass, as in this case, with 73% of the lesions < 3 cm. Symptoms reported with SH include hemoptysis, chronic cough, or chest pain. On chest radiograph, SH typically presents as a peripheral, solitary, round, well-defined homogeneous opacity, without predilection for a particular lobe, with diameters ranging from 1.3 to 8.2 cm. Calcification is seldom seen, and cavitation does not occur. Chest CT scan demonstrates a round nodule or mass with smooth margins that shows inhomogeneous enhancement with contrast, which is not specific for SH but suggests a benign process. Other signs reported with SH include marginal pseudocapsule, overlying vessel, air gap, and halo signs. SH is rarely bilateral, and lymph node metastasis is extremely rare and does not appear to affect long-term survival. 18 F-fluorodeoxyglucose (FDG) PET scan cannot be reliably used to differentiate this tumor from malignant origin because a substantial number of reported cases have shown false positivity to FDG (SUV > 2.5).

Given the peripheral location of most SHs, the usual approach to diagnosis begins with CT-guided fine needle aspiration (FNA). FNA with cell block preparation and immunohistochemical evaluation can be diagnostic. The diagnosis of SH is usually made based on the stromal component and epithelial component composed of two types of cells, surface cells and round cells. However, this distinct separation into cell types may not be possible because there is often transition present, and this can be easily confused for well-differentiated adenocarcinoma of the lung or adenocarcinoma in situ, because the epithelial cells of the SH cannot be distinguished from that of well-differentiated adenocarcinoma. Presence of nuclear pleomorphism, mitotic figures, irregular nuclear contour and prominent nucleoli, and cytologic atypia help differentiate adenocarcinoma from SH. Besides, adenocarcinoma does not show two cell types or presence of hyalinized stroma. Other close differentials include carcinoid tumor, which is differentiated based on positivity for neuroendocrine markers, metastatic renal cell cancer, which usually shows marked nuclear atypia, and increased vascularity, unlike SH and metastatic papillary thyroid cancer, which is easily identified based on positivity for thyroglobulin on immunohistochemistry.

SHs of the lung are generally considered benign lesions, and surgical resection with extracapsular enucleation is curative without the need of additional treatment. Because of the paucity of data about SH, given the rare occurrence of these tumors, it is unclear if small tumors could be observed over time. However, because FNA is not diagnostic and PET scan positivity is reported in many cases, surgical excision is eventually performed and is the preferred approach. Lymph node dissection in cases of large SH or with enlarged lymph nodes may be required. Lymph node involvement, multiple and bilateral SH, recurrence of SH, and presence of pulmonary metastases have been reported, which suggest that SH may have low malignant potential; however, presence of any of these features have not been associated with worse prognosis or increase in mortality.

Clinical Course

Initial pathologic review of CT-guided biopsy was misread as adenocarcinoma of the lung based on immunostain results. Pathologic evaluation of lobectomy specimen revealed dual population of cells with surface cuboidal cells and underlining round stromal cells showing a solid pattern of growth, which merged with a sclerotic pattern composed of sheets of collagen with occasional dilated vascular spaces. Immunostains showed positivity for TTF-1, Cytokeratin 7, and Napsin A in surface cells and vimentin positivity in the stromal cells, revealing a dual population of cells which was consistent with SH of the lung (Figs 2A, 2B). Post hoc review of the initial biopsy was still considered to be consistent with adenocarcinoma because dual population of cells seen on the surgically excised specimen was not present and immunostaining was highly suggestive of adenocarcinoma. The initial abdominal pain that the patient had resolved, and she is doing well on follow-up a year later, with no recurrence found on surveillance scans.

Figure 2
Figure Jump LinkFigure 2 A, Hematoxylin and eosin stain image showing sclerotic (thin arrow) and hemorrhagic (thick arrow) architectural pattern (20×). B, Hematoxylin and eosin stain image showing surface cuboidal cells (thin arrow) and underlining round stromal cells (thick arrow) with solid growth pattern (20×).Grahic Jump Location

  • 1.

    SH of the lung is a very rare benign lung neoplasm that typically occurs predominantly in middle-aged women and originates from primitive respiratory epithelium, specifically type II pneumocytes, hence the alternate name pneumocytoma.

  • 2.

    Radiologically, it presents usually as a peripheral, solitary, well-defined nodule or mass without any predilection for a particular lobe and can demonstrate an FDG uptake with high SUV (> 2.5) on PET scans.

  • 3.

    FNA is often nonconclusive for SH, and pathology can be mistaken for malignancy, particularly adenocarcinoma of the lung.

  • 4.

    Surgical excision is curative for SH without additional treatment.

Financial/nonfinancial disclosures: None declared.

Other contributions:CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met.


Figures

Figure Jump LinkFigure 1 A, Chest CT scan mediastinal window showing left lobulated lung mass abutting the left pleura and chest wall. B, PET scan demonstrating 18 F-fluorodeoxyglucose-avid left lower lobe mass.Grahic Jump Location
Figure Jump LinkFigure 2 A, Hematoxylin and eosin stain image showing sclerotic (thin arrow) and hemorrhagic (thick arrow) architectural pattern (20×). B, Hematoxylin and eosin stain image showing surface cuboidal cells (thin arrow) and underlining round stromal cells (thick arrow) with solid growth pattern (20×).Grahic Jump Location

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