K.E.M.
Radiology
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Department of Radiology
Seth G.S. Medical College and K.E.M. Hospital, Mumbai , India
Case of the Month
Submandibular epidermal inclusion cyst
Contributed by: Swaksh Nemani, Jui Nigudkar, Aishwarya Dahake
Introduction :
Epidermoid or epidermal inclusion cysts are formed by the proliferation of epidermal cells within a defined dermal space. Epidermoid cysts can occur at any age, but are more frequent in adulthood. These differ from dermoid cysts in the lack of dermal appendages. The face, neck, periauricular area, and upper trunk are more commonly involved.
Here we report on one such cyst in an adult male
Clinical Profile:
A 40 year old man came with complaints of a swelling in the right submandibular region, gradually increasing in size since three years. He had no history of trauma, pain, local warmth or any discharge. The swelling was soft and mobile without local rise of temperature.
Radiological findings:
1. On frontal and lateral radiographs of the neck, there was a soft tissue swelling in the anterior aspect of the neck in the midline with extension to the right. There were no internal foci of calcification or lucencies and no erosion or periosteal reaction in the mandible. There was no compression of the airway.
2. On Ultrasound examination in B mode and colour Doppler, with a linear transducer at 9 MHz frequency, there was a well-defined, hypoechoic, cystic lesion superficial to the strap muscles with increased through transmission. There were numerous round, ball-like hyperechoic lesions and few linear hyperechoic strands occupying the cystic lesion. The lesion showed no vascularity. Based on ultrasound findings and typical appearance, a provisional diagnosis of dermoid cyst of the neck was made.
3. An MRI with contrast showed a well-defined, superficial, T1/T2 hyperintense cystic lesion in the right sub-mandibular region superficial to the supra-hyoid strap muscles. It contained numerous T1/T2 hyperintense round lesions. There was no suppression of the T1 hyperintense lesions within the cyst on fat-saturation and no contrast enhancement of the lesions or the cyst. DWI and ADC map showed diffusion restriction of the lesions within the cyst with corresponding drop-out on ADC map suggesting true diffusion restriction.
FIG 1A & 1B
Frontal (A) and lateral (B) clinical images showed a round, swelling in the right sub-mandibular region with no pus point or overlying skin changes.
FIG 2A & 2B
Frontal (A) and lateral (B) radiographs of the neck showed a soft tissue swelling in the anterior aspect of the neck in the midline with extension to the right. There were no internal foci of calcification or lucencies and no erosion or periosteal reaction in the mandible. There was no compression of the airway.
Grou
FIG 3A & 3B
B mode (A) and Color Doppler (B) axial images of ultrasound with a linear transducer at 9 MHz frequency showed a well-defined, hypoechoic, cystic lesion superficial to the strap muscles with increased through transmission. There were numerous round, ball-like hyperechoic lesions and few linear hyperechoic strands occupying the cystic lesion. The lesion showed no internal vascularity.
FIG 4
B mode sagittal image of ultrasound with a linear transducer at 9 MHz frequency showed the lesion cranial to the thyroid gland and superficial to the strap muscles of the neck.
FIG 5A & 5B
T1WI (A) and T2WI (B) of axial sections of MRI neck without contrast showed a well-defined, superficial, T1/T2 hyperintense cystic lesion in the right sub-mandibular region superficial to the supra-hyoid strap muscles. It contained numerous T1/T2 hyperintense round lesions.
FIG 6A & 6B
T1WI fat-saturation without (A) and with (B) gadolinium based contrast axial sections of MRI neck showed no suppression of the T1 hyperintense lesions within the cyst on fat-saturation and no contrast enhancement of the lesions or the cyst.
FIG 7A & 7B
DWI and ADC map axial sections of MRI neck showed diffusion restriction of the lesions within the cyst with corresponding drop-out on ADC map suggesting true diffusion restriction.
FIG 8A & 8B
Intra-operative (A) and gross specimen (B) images of the cyst removed by surgical excision.