PMC5462915_01
Computed tomography of the chest demonstrated a round-shaped, poorly enhancing mass with cystic portions measuring 2.7 cm at the right anterior cardiophrenic angle in the axial (A) and coronal (B) images. This lesion was observed on an incidenta abdominal CT scan taken 3 years ago. (C) Magnetic resonance imaging of the chest showed a lobulating mass at the right anterior cardiophrenic angle, with intermediate signal intensity on the T1-weighted image (D) and high signal intensity on the T2-weighted image (E).
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F1
Contrast-enhanced computed tomography (CT) of the thorax showed a round-shaped mass with cystic components measuring approximately 27 mm x 21 mm at the right anterior cardiophrenic angle, with a partial contrast enhancement (Figures 1A,B). The mass was unchanged over 3 years based on an incidental abdominal CT scan owing to acute cholecystitis (Figure 1C). On chest MRI, a lobulating nodule was found corresponding to the location indicated by CT (Figures 1D,E).
The carcinoid tumor (bold arrow) and necrotizing granuloma (thin arrow) were in close proximity [hematoxylin and eosin (H&E) stain, x12.5] (A). The tumor consisted of uniform polygonal cells with a salt-pepper chromatin pattern (H&E stain, x400) (B). Upon immunohistochemical staining, the tumor was immunoreactive for CD 56 (C), synaptophysin (D), and adrenocorticotropic hormone (E). The Ki-67 index was very low (<2%) (F). A lesion abutting the carcinoid tumor exhibited chronic granulomatous inflammation with necrosis (H&E stain, x400) (G). Gomori methenamine-silver stain revealed acutely branching and septated fungal hyphae within the necrotic tissue (x400) (H).
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F2
Microscopically, the two lesions were in very close proximity, presenting as one lesion radiographically (Figure 2A). The tumor consisted of uniform polygonal cells with finely granular chromatin and low mitotic activity, which histologically favored a typical carcinoid lesion (Figure 2B). This confirmed the final diagnosis of a carcinoid tumor with ACTH expression (Figures 2C-F). The adjacent grayish yellow mass exhibited chronic necrotizing granulomatous inflammation with Aspergillus, highlighted by Gomori methenamine-silver staining (Figures 2G,H).