case_images: PMC11217165_01
case_images: Various imaging findings of ectopic parathyroid adenoma in the sternocleidomastoid muscle. (A) Axial image in contrast-enhanced CT showed a soft tissue lesion (arrow). (B) Sagittal image in contrast-enhanced CT showed a soft tissue lesion (arrow). (C) Conventional ultrasound Showed a well-defined slightly hyperechoic mass. (D) Early (15 minutes) images in Tc-99m-MIBI scintigraphy showed a cord-like high uptake in the projection area of the left sternocleidomastoid muscle. (E) late (2 hours) images in Tc-99m-MIBI scintigraphy still showed a cord-like high uptake in the projection area of the left sternocleidomastoid muscle.
case_images: fonc-14-1410057-g001.jpg
case_images: PMC11217165_01_fonc-14-1410057-g001.jpg
case_images: f1
case_images: CT images revealed a spindle-shaped soft tissue lesion with clear borders in the left sternocleidomastoid muscle, showing homogeneous hyperenhancement. Conventional ultrasound ( Figure 1C ) identified a well-defined slightly hyperechoic spindle-shaped lesion (measuring 40 mm x 17 mm x 9 mm) in the left sternocleidomastoid muscle with color Doppler displaying abundant blood flow signals, raising suspicion of a myogenic tumor. Early ( Figure 1D , 15 minutes) and late ( Figure 1E , 2 hours) images in Tc-99m-MIBI scintigraphy both exhibited well-defined, regularly shaped, cord-like high uptake in the projection area of the left sternocleidomastoid muscle.
case_images: Pathological findings of ectopic parathyroid adenoma in the sternocleidomastoid muscle. (A) Image of hematoxylin-eosin (magnification, x50) showed the mass occurred in striated muscle tissue. (B) Image of hematoxylin-eosin (magnification, x100) showed conspicuous follicular structures, concomitantly with tumor cells exhibiting a palisade arrangement around blood vessels (arrow). (C) Immunohistochemistry result showed a strong positive expression of parathyroid hormone (magnification, x100).
case_images: fonc-14-1410057-g002.jpg
case_images: PMC11217165_01_fonc-14-1410057-g002.jpg
case_images: f2
case_images: Early ( Figure 1D , 15 minutes) and late ( Figure 1E , 2 hours) images in Tc-99m-MIBI scintigraphy both exhibited well-defined, regularly shaped, cord-like high uptake in the projection area of the left sternocleidomastoid muscle. Hematoxylin and eosin staining ( Figures 2A, B ) of the lesion showed the adenoma growing within the striated muscle, and conspicuous follicular structures, concomitantly with tumor cells exhibiting a palisade arrangement around blood vessels. Immunohistochemistry revealed a strong positive expression of parathyroid hormone ( Figure 2C ).