PMC4449922_01
Transverse (a) and color Doppler (b) images of ultrasonography show an irregular mass with an indistinct margin, internal hypoechogenicity, and increased peripheral vascularity.
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Ultrasonography (US) showed a mass with an irregular shape, indistinct margin, internal hypoechogenicity, and increased peripheral vascularity (Figure 1).
Axial (a) and coronal (b) chest computed tomography images show a 12 cm mass with a lobulated contour and heterogeneous enhancement in the right axilla.
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Computed tomography (CT) scan of the chest was performed to characterize the right axillary mass and it indicated the presence of a 12 cm mass with a lobulated contour and heterogeneous enhancement in the right axilla (Figure 2).
18F-FDG-PET scan shows two focal FDG-avid uptakes in the right axilla (SUV max 12.7, black arrow) and right adrenal gland (SUV max 4.7, white arrow). SUV max: maximum standardized uptake value. 18F-FDG-PET: 18F-fluorodeoxyglucose-positron emission tomography.
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FDG-avid uptake in the right axilla with a maximum standardized uptake value (SUV max) of 12.7 and also showed a focal FDG-avid uptake in the right adrenal gland with an SUV max of 4.7 (Figure 3). For further evaluation of the newly found mass in the adrenal gland, CT of the abdomen and pelvis was performed and a 1.5 cm mass with lobulated contours and mild enhancement was observed in the right adrenal gland, directly invading the liver (Figure 4).
Axial (a) and coronal (b) abdominal computed tomography images during the late arterial phase show a 1.5 cm mass with a lobulated contour and mild enhancement in the right adrenal gland (black arrow).
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FDG-avid uptake in the right axilla with a maximum standardized uptake value (SUV max) of 12.7 and also showed a focal FDG-avid uptake in the right adrenal gland with an SUV max of 4.7 (Figure 3). For further evaluation of the newly found mass in the adrenal gland, CT of the abdomen and pelvis was performed and a 1.5 cm mass with lobulated contours and mild enhancement was observed in the right adrenal gland, directly invading the liver (Figure 4).
Microscopic findings of the right axillary mass showed diffuse sheets of basophilic tumor cells ((a) HE x200) with large and pale staining nucleus and tiny nucleoli ((b) HE x400). Lymphovascular invasion is an almost constant histological finding ((c) HE x400). Characteristic paranuclear dot-like staining of CK20 is specific for MCC ((d) CK20 x400).
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Histologic examination confirmed that the right axillary mass was a neuroendocrine carcinoma, composed of diffuse sheets of basophilic tumor cells with vesicular nuclei, small nucleoli, and scanty cytoplasm (Figures 5(a) and 5(b)). Lymphatic and vascular infiltrations were frequently identified (Figure 5(c)). Immunohistochemical staining of cytokeratin (CK) 20 was expressed in the paranuclear globules of the tumor cells in the punctate perinuclear dot-like pattern (Figure 5(d)).
Histopathology of the adrenal gland mass showed similar findings observed in the axillary mass but had adopted more spindled cell morphology (HE x400).
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Histologic examination of the right adrenal gland revealed tumor cells almost identical to the axillary mass except the slight spindle cell morphology (Figure 6).