Answer for BIR CoW 09 Jun 2024
Left parotid sialolithiasis with chronic sialadenitis
Findings
Computed tomography images shows multiple hyperdense calculi noted in left stenson’s duct. MR sialogram revealed multiple filling defects in stensons duct involving oblique part with dilatation of intraglandular and extraglandular duct reflecting sialolithiasis. Left parotid gland appears reduced in size in comparison with the right with T1 /T2 hypointesity noted in the left parotid gland reflecting chronic parotiditis. Volume rendered images shows dilated stensons duct. Impression: Feature suggestive of left parotid sialolithiasis with chronic sialadenitis.
Discussion
Sialolithiasis is the most common disease of salivary glands, accounting for approximately 50% of all major salivary gland pathology. The submandibular salivary gland is most commonly affected (80-90% of cases) with almost all the remaining cases located in the parotid duct. This is primarily believed to be due to the increased viscosity of the secretions from the submandibular gland . Sialolithiasis is a disease of adults, typically between 30 and 60 years of age. There is a male predilection. Plain radiograph: Not all stones are radiopaque. Plain radiography is able to visualize only 80-90% of submandibular stones (which are usually located in the duct ) and ~60% of parotid duct stones (more frequently found within the gland itself) presumably due to differences in the composition of the secretion of the parent glands. Oblique views are often required to project the stones away from adjacent bone and teeth. Ultrasound: Stones appear as strongly hyperechoic lines or points with distal acoustic shadowing represent stones. Small stones (<2 mm) may however not shadow. Ultrasound is able to visualize stones that are radiolucent. In acute obstructive cases, the gland appears enlarged and excretory ducts proximal to the stone may be visibly dilated. The examination is best performed with small high-frequency intraoral probes. CT: CT is excellent at visualizing stones both within the duct and within the gland. The spatial resolution is not as high as plain radiography and as such very small stones may not be evident. In acute obstructive cases, the gland may appear enlarged, hyperdense and associated with stranding and enhancement following contrast administration. In chronic cases, fatty atrophy will be evident, with the parenchyma reduced in volume and replaced by fat. MRI: MRI is able not only to visualize larger stones but able in many instances to map the ductal anatomy and to assess the gland. Stones appear as low signal regions (on all sequences) outlined by high signal saliva on T2 weighted images. MRI is able to distinguish acute from chronic obstruction as well as glands with only incomplete obstruction. In the acute setting, glands are enlarged and demonstrate inflammatory changes: T1: reduced signal compared to the other side T2: increased signal (best seen on fat suppressed sequences) In chronic cases, the gland is reduced in size and demonstrates fatty atrophy : T1: increased signal compared to the other side T2: a reduced signal of gland parenchyma which is itself reduced in amount In cases where a small non-obstructive sialolith is present, the gland may appear entirely normal. Differential diagnosis Hemangioma / phlebolith Atherosclerotic calcification Filling defects on sialography may be caused by: An injected bubble of air Tumor Blood clot
Findings
Computed tomography images shows multiple hyperdense calculi noted in left stenson’s duct. MR sialogram revealed multiple filling defects in stensons duct involving oblique part with dilatation of intraglandular and extraglandular duct reflecting sialolithiasis. Left parotid gland appears reduced in size in comparison with the right with T1 /T2 hypointesity noted in the left parotid gland reflecting chronic parotiditis. Volume rendered images shows dilated stensons duct. Impression: Feature suggestive of left parotid sialolithiasis with chronic sialadenitis.
Discussion
Sialolithiasis is the most common disease of salivary glands, accounting for approximately 50% of all major salivary gland pathology. The submandibular salivary gland is most commonly affected (80-90% of cases) with almost all the remaining cases located in the parotid duct. This is primarily believed to be due to the increased viscosity of the secretions from the submandibular gland . Sialolithiasis is a disease of adults, typically between 30 and 60 years of age. There is a male predilection. Plain radiograph: Not all stones are radiopaque. Plain radiography is able to visualize only 80-90% of submandibular stones (which are usually located in the duct ) and ~60% of parotid duct stones (more frequently found within the gland itself) presumably due to differences in the composition of the secretion of the parent glands. Oblique views are often required to project the stones away from adjacent bone and teeth. Ultrasound: Stones appear as strongly hyperechoic lines or points with distal acoustic shadowing represent stones. Small stones (<2 mm) may however not shadow. Ultrasound is able to visualize stones that are radiolucent. In acute obstructive cases, the gland appears enlarged and excretory ducts proximal to the stone may be visibly dilated. The examination is best performed with small high-frequency intraoral probes. CT: CT is excellent at visualizing stones both within the duct and within the gland. The spatial resolution is not as high as plain radiography and as such very small stones may not be evident. In acute obstructive cases, the gland may appear enlarged, hyperdense and associated with stranding and enhancement following contrast administration. In chronic cases, fatty atrophy will be evident, with the parenchyma reduced in volume and replaced by fat. MRI: MRI is able not only to visualize larger stones but able in many instances to map the ductal anatomy and to assess the gland. Stones appear as low signal regions (on all sequences) outlined by high signal saliva on T2 weighted images. MRI is able to distinguish acute from chronic obstruction as well as glands with only incomplete obstruction. In the acute setting, glands are enlarged and demonstrate inflammatory changes: T1: reduced signal compared to the other side T2: increased signal (best seen on fat suppressed sequences) In chronic cases, the gland is reduced in size and demonstrates fatty atrophy : T1: increased signal compared to the other side T2: a reduced signal of gland parenchyma which is itself reduced in amount In cases where a small non-obstructive sialolith is present, the gland may appear entirely normal. Differential diagnosis Hemangioma / phlebolith Atherosclerotic calcification Filling defects on sialography may be caused by: An injected bubble of air Tumor Blood clot
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!