Pulmonary sarcoidosis presenting as a solitary nodule mimicking lung cancer

Abstract

Nodular sarcoidosis is a rare form of sarcoidosis. It is difficult to differentiate from malignancy based on radiological findings. Histological examination is important, and sarcoidosis should be considered as differential diagnosis of solitary lung nodule.

Nodular sarcoidosis is a rare form of sarcoidosis. It is difficult to differentiate from malignancy based on radiological findings. Histological examination is important, and sarcoidosis should be considered as differential diagnosis of solitary lung nodule.

Sarcoidosis shows various clinical and radiologic manifestations. Nodular sarcoidosis is an uncommon form of pulmonary sarcoidosis. Cases presenting as solid nodules are especially rare. We herein present a case of nodular sarcoidosis with a solid nodule that was suspected to be lung cancer.

A 67‐year‐old woman with no significant medical history was referred to our hospital for the evaluation of an abnormal shadow on the chest radiograph.

She was asymptomatic. She was a nonsmoker. Physical examination was normal. Laboratory tests showed mildly elevated C‐reactive protein levels. Lung cancer tumor markers and angiotensin‐converting enzyme were within the normal range. Computed tomography (CT) showed a solitary nodule with spicula in the S⁶ of the right lung (Figure 1). Positron emission tomography (PET)/CT scan showed mild fluorodeoxyglucose uptake in the nodule and the right hilar lymph node in the delay phase (Figure 2). Transbronchial biopsy of specimens demonstrated no malignant findings. We performed video‐assisted thoracoscopic lung surgery for the nodule in the right lower lobe, which revealed noncaseating granulomas consistent with sarcoidosis (Figure 3). Acid‐fast bacilli stain and tissue cultures were negative. Histologic findings established a diagnosis of sarcoidosis.

FIGURE 1.

Chest CT shows a solitary nodule with spicula measuring 3 cm × 2 cm in the S⁶ of the right lung

FIGURE 2.

PET scan exhibits fluorodeoxyglucose uptake in the right lower lobe nodule (maximum standardized uptake value [SUVmax] 3.8) and the right hilar lymph node (SUVmax 3.6) in the delay phase

FIGURE 3.

Pathological examination of the specimen using thoracoscopic lung surgery reveals noncaseating granulomas (hematoxylin and eosin stain, ×100 (A) ×400 (B))

Nodular sarcoidosis is an uncommon form of sarcoidosis prevalent in 2.4‐4% of cases. ¹ Most patients present with multiple lung nodules. Solitary lung nodule is a rare radiologic finding in about 18% of nodular sarcoidosis, ¹ which is coalescence of individual granulomas. ² It is difficult to differentiate from malignancy based on radiologic findings. Histological examination is necessary to establish an accurate diagnosis.

CONFLICT OF INTEREST

None declared.

AUTHOR CONTRIBUTIONS

TT: contributed to write‐up of abstract, case presentation, and images. TN: reviewed and edited the manuscript.

ETHICAL APPROVAL

The ethics approval was not necessary for this case report. All patient's data and images are de‐identified.

INFORMED CONSENT

Written informed consent was obtained from the patient for publication of this case report.

Taketa T, Nakamura T. Pulmonary sarcoidosis presenting as a solitary nodule mimicking lung cancer. Clin Case Rep. 2021;9:e4208. 10.1002/ccr3.4208

DATA AVAILABILITY STATEMENT

Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study.