Necrotizing sarcoid granulomatosis simulating pulmonary malignancy: A case report

Abstract

Rationale: Necrotizing sarcoid granulomatosis (NSG) has recently been termed "sarcoidosis with NSG pattern" for the disease entity representing nodular sarcoidosis with granulomatous pulmonary angiitis. It is characterized by sarcoid-like granulomas, vasculitis, and a variable degree of necrosis. Its rarity and nonspecific clinical symptoms can easily lead to misdiagnosis or delayed diagnosis.

Patient concerns: We report a 67-year-old female with a biopsy-confirmed sarcoidosis with NSG pattern mimicking pulmonary malignancy on initial chest computed tomography scan.

Diagnoses: Sarcoidosis with NSG pattern.

Interventions: The patient underwent video-assisted thoracoscopic surgery with a lung biopsy. No further treatment was performed after the lung biopsy.

Outcomes: Follow-up imaging studies revealed spontaneous regression of the disease after 2 months.

Lessons: Awareness of this rare benign disease entity and overlapping radiologic manifestations with pulmonary malignancy or other granulomatous diseases can be helpful for making a precise diagnosis with a better differential diagnosis.

Figure 1

An initial chest radiography for a 67-year-old woman. (A,B) Initial chest radiographs showing lobulated nodular opacities in the right middle lobe and the left lower lobe (arrows).

Figure 2

An initial contrast-enhanced chest CT performed at referring center two weeks before visiting our hospital. (A,B) On lung window setting, 2 lobulated nodules are seen in the right middle lobe and the left lower lobe (arrows). (C—F) On mediastinal window setting, there is right lower paratracheal and right hilar lymphadenopathy with homogenous enhancement without necrosis (open arrows in C,D). Contrast enhancement of the nodules in the right middle lobe and the left lower lobe is seen (arrows in E,F). The nodule in the right middle lobe shows peripheral lobulation and air-bronchogram. Another solid nodule in the left lower lobe also shows slight lobulation.

Figure 3

A fluorine 18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography scan performed at our hospital at 10 days after the initial visit. (A—D) FDG uptakes in the right lower paratracheal and right hilar lymphadenopathy are shown (open arrows in A,B). Avid FDG uptakes are also noted in the nodules in the right middle lobe and the left lower lobe (maximum standardized uptake values: 10.0 and 8.5, respectively) (arrows in D). Other 2 small hypermetabolic nodules are newly revealed in the right middle lobe and the left lower lobe (arrowheads in C,D).

Figure 4

A follow-up contrast-enhanced chest CT performed at our hospital at 1 month after the initial chest CT scanning at the referring center. (A—D) On lung window setting, enlargement of pulmonary nodules (arrows) and newly appeared nodules in the right middle lobe and the left lower lobe are seen (arrowheads). Peribronchovascular distribution of the pulmonary nodules is well demonstrated (arrows). (E,F) On mediastinal window setting, nodules in left lower lobe show areas of low attenuation (arrows) representing necrosis.

Figure 5

Pathologic findings of a lung specimen obtained from video-assisted thoracoscopic surgery of the left lower lobe. (A) On microscopy, the lung nodule in left lower lobe shows exuberant inflammatory nodules with multifocal necrosis (hematoxylin staining, × 1.25). (B) Large zone of necrosis (arrows) and multiple granulomas (dotted circle) are seen (hematoxylin staining, × 10). (C) Confluent non-necrotizing sarcoid-like granulomas with epithelioid cells and multinucleated giant cells (arrows) are observed (hematoxylin staining, × 20). (D) Vasculitis with lymphoplasmacytic infiltration is also well shown (arrows) (hematoxylin staining, × 40).