Tabassum K. Belim, MD

 An 18-year-old boy with complaints of swelling in floor of mouth since childhood and difficulty with movement of tongue. On physical examination, sublingual large swelling was noted. Overlying surface was reddish, however no signs for active inflammation seen. Ultrasound, contrast enhanced CT scan and MRI were done.

On imaging, sublingual dermoid cyst with classical “Sack of Marbles” appearance on MRI was diagnosed.

Figure 1: Transverse grey-scale ultrasound image shows a well-defined, lobulated cystic lesion with internal echoes (arrows) in the submental region in midline.

Figures 2a and b: Axial (2a) and sagittal (2b) CT images show a well-defined, homogenous, hypo-attenuating mass of approximate size (30 x 60 x 42) mm located in midline between two genioglossus muscle. It lies above the mylohyoid muscle, demarcating the location in floor of mouth and not sub mental space. Also noted is bilateral obstructed opening of wharton’s ducts and resultant dilatation.

Figures 3a, b and c: T1W axial (3a), T2W axial (3b) and T2W sagittal (3c) MRI scans show a well circumscribed mass lesion sharply circumscribed cystic mass lesion in floor of mouth , displacing mylohyoid muscle inferiorly, which appear hypointense on T1W and hyperintense on T2W images. T2-weighted MRI image shows the characteristic appearances of a midline dermoid cyst in the floor of mouth with a “sack of marbles” appearance due to presence of fat globules (arrowheads) within the dermoid cyst.)

Figures 4a and b: Per-operative (4a) and specimen (4b) images followed by histopathological study confirmed the diagnosis.

 Ultrasound findings show a well defined hypo echoic lesion in sublingual space with internal echoes and few twinkling artifacts.

CT scan findings show a well defined nonenhancing low attenuation unilocular cystic lesion in midline of sublingual space. The lesion displaces both midline genioglossus muscles laterally and mylohyoid muscle inferiorly. No evidence of any internal fat density or calcified foci was noted. The cystic lesion obstructs opening of Wharton’s duct bilaterally with resultant proximal dilatation.

MRI findings include a well defined cystic mass in the floor of the mouth having smooth margins, which follow intermediate T1-weighted and high T2-weighted signal intensity. The mass lies above the mylohyoid muscle.

 Dermoid benign teratoma is a developmental pathology. The occurrence of dermoid cyst in head and neck region varies between 7 percent and 10 percent. The floor of mouth (sublingual, sub mental and sub mandibular regions) is second most common site after orbit. The most popular theory regarding the origin of these lesions suggests that they are derived from epithelial rests which become enclosed during midline closure of the first and second branchial arches.

Dermoid cyst is generally a painless slow growing swelling. They can manifest between five and 50 years of age with younger population affected predominantly. The male to female ratio is 3:1.

On CT, dermoid cysts commonly appear as low-attenuation, well-circumscribed, unilocular masses, hypo dense than muscle, that with or without presence of fat. The density of internal fatty content vary between (-10 to -100 HU).The wall of the cyst usually enhances following contrast administration.

MRI is an accurate, radiation-free, non-invasive modality for the diagnosis and helps in follow-up evaluation for lingual dermoid cyst. It has the advantage to delineate the cyst and precise its possible extension through the floor of the mouth. On MR imaging, Dermoid lesions have variable appearance, depending upon their fat content, being either hypointense or hyperintense to muscle on T1W images and typically hyperintense on T2W sequences. The characteristic appearances of a midline dermoid cyst in the floor of mouth is a “sack of marbles” appearance due to presence of fat globules on T2W images. A very close differential of dermoid cyst is an epidermoid cyst, which can be differentiated on MRI. Epidermoid cyst typically shows restricted diffusion on diffusion weighted images because of internal thick keratinaceous material.

The relationship between cyst and mylohyoid muscle is of great surgical importance. As intra-oral approach avoids cosmetic scar, preserves mylohyoid muscle function with a faster recovery. However, lesions that lie inferior to the mylohyoid muscle (submental and submandibular cysts) must usually be removed via an external approach. Multiplanar imaging in axial, coronal and sagittal planes are useful in this regard.In our case, as the cyst lies above the mylohyoid muscle, surgical removal was done by an intraoral approach.


1. Batsakis J. Teratomas of the head and neck. In: Batsakis J, ed. Tumors
of the Head and Neck: Clinical and Pathological Considerations, 2nd ed. Baltimore: Williams &Wilkins, 1979;226–232.
2. Worley C, Laskin D. Coincidental sublingual and submental epidermoid cysts. J Oral Maxillofac Surg 1993;51:787–790.
3. Vogl T, Steger W, Ihrer S, Ferrera P, Grevers G. Cystic masses in the floor of the mouth: value of MR imaging in planning surgery. AJR 1993;161:183–186.

Dr. Tabassum K. Belim, Dr. N.U. Bahri, Dr. S. L. Chudasama
Department of Radiodiagnosis, M. P. Shah Medical College, Jamnagar, Gujarat, India

Articles

An 18-year-old boy with complaints of swelling in floor of mouth since childhood and difficulty with movement of tongue. On physical examination, sublingual large swelling was noted. Overlying surface was reddish, however no signs for active inflammation seen. Ultrasound, contrast enhanced CT scan and MRI were done. 

Sublingual Dermoid Cyst

A young girl presented with complaints of dysmenorrhea and cyclic pelvic pain for one year. She had normal menarche and regular menstrual cycle. On physical examination there was tenderness in right lower quadrant.

Figure 1. USG shows two widely separated uterine corpii, a non obstructed normal appearing left uterus [Fig. 1a] ,and hematometra, hematosalpinx in right uterus [Fig. 1b], normal right ovary and hematometra in right uterus [Fig. 1c].

Figure 2. Axial T2W AND T1W images show widely divergent uterine horns, non-obstructing normal left uterus, and hematometra and hematosalpinx in obstructed right uterus.

Figure 3. Sagittal T2WI images reveal two separate uterine corpi with right blind ended uterus. Figure 3b shows non-obstructed uterus opening into vagina.

Figure 4. Coronal T2WI images of abdomen show ipsilateral renal agenesis on right side.

Figure 5. Schematic diagram shows uterine didelphys with unilateral vaginal agenesis and ipsilateral renal agenesis.

Diagnosis: Uterine didelphys with unilateral vaginal agenesis and ipsilateral renal agenesis (OHVIRA)

Findings: Ultrasound findings show two widely separated uterine corpi, a non-obstructed normal appearing left uterus and cervix, and hematometra, hematosalpinx in right uterus.

MRI findings include widely divergent uterine horns, non-obstructing normal left uterus and cervix opening into vagina which communicates with external opening, and hematometra and hematosalpinx in obstructed right uterus which ends as a blind end cavity and does not show any communication with vagina suggestive of vaginal agenesis.

Additional imaging of urinary system shows renal agenesis on right side.

Discussion: Mullerian duct anomalies are congenital anomalies which results from non-development, defective vertical or lateral fusion, or resorption failure of mullerian (paramesonephric ) ducts. MDA have been classified by American Society of Reproductive Medicine according to patients clinical presentation, treatment and prognosis(1).

I Müllerian agenesis or hypoplasia
II Unicornuate uterus
III Uterus didelphys
IV Bicornuate uterus
V Septate uterus
VI Arcuate uterus
VII DES-related uterine anomalies

Classification of Vaginal Anomalies
I Transverse vaginal septum (obstructing or non-obstructing)
II Longitudinal vaginal septum (obstructing or non-obstructing)
III Stenosis or iatrogenic cause

OHVIRA syndrome is typically associated with type III MDA (uterine didelphys) with two uteri, two cervices and two vaginas,one of which is obstructed ,and associated with renal agenesis on the side of hemivaginal obstruction, but this case is a variant of described OHVIRA as it was renal agenesis with ipsilateral complete vaginal agenesis instead of vaginal obstruction by transverse (type I) or longitudinal (II)vaginal septum.

OHVIRA results from embryonic arrest at eight weeks of gestation which affects adjacent mullerian and metanephric ducts. The defect may also occur as early as the fourth week of gestation and can affect both the mesonephric ducts and ureteral buds. The mesonephric duct, which is maldeveloped, does not allow crossover of the mullerian duct and consequent fusion results in a didelphys uterus and obstruction of the ipsilateral horn and the vagina(2).

Clinically, patients with OHVIRA usually present due to symptoms from obstruction. Almost uniformly this presentation occurs at or after menarche when the hemiuterus or hemivagina becomes symptomatic and the patient experiences cyclical dysmenorrhea. This results in retrograde menstrual flow and may present as a unilateral abdomino-pelvic mass on physical examination. Complications associated with this disorder are endometriosis, pyosalphinx, pyocolpos and pelvic adhesions.

Imaging is usually done when patient presents with complaints of abdominopelvic pain and cyclic dysmenorrheal. Since the other non obstructive uterus is normally functional, infertility is a rare presentation. Ultrasound findings include two widely separated uterine corpii, a non-obstructed normal appearing uterus and cervix opening into vagina, hematometra and hematosalpinx in other uterus, however exact cause of obstruction is difficult to evaluate on sonography and further imaging is required.

MRI is the imaging investigation of choice in such cases due to multiplanar capabilities, high soft tissue contrast and no risk of radiation. MRI findings include non-obstructing normal uterus and cervix opening into vagina which communicates with external opening. Hematometra and hematosalpinx in obstructed uterus which ends as a blind end cavity, and does not show any communication with vagina suggestive of vaginal agenesis.

Imaging of urinary system is imperative to perform in presence of mullerian duct anomalies or vice versa. Differential diagnosis is uterine didelphys with hemivaginal obstruction by transverse or longitudinal vaginal septum or imperforate hymen.

(1) Beatriz L P Junqueira ,MD, Lisa M Allen MD,FRCSC,Rachel FSpitzer, MD,BSc,MPH,FRCSC,Kerith L Lucco,MD ,Paul s Babyn,MD,CM,Andrea S Doria, MD,PhD,MSc,mullerian duct anomalies and mimics in children and adolescents-corelative intraoperative assessment and clinical imaging .radiographics 2009;29:1085-1103

(2) Luther Adair II, Maria Georgiades2, Rhonda Osborne, Tsz Ng, Uterus didelphys with unilateral distal vaginal agenesis and ipsilateral renal agenesis: Common presentation of an unusual variation Radiology Case. 2011 Jan; 5(1):1-8

Reeta B.Gupta, MD, N.U. Bahri, MD, and Tabassum K. Belim, MD, 

Department of Radiodiagnosis, M.P. Shah Medical College, Jamnagar, Gujarat, India.

A young girl presented with complaints of dysmenorrhea and cyclic pelvic pain for one year. She had normal menarche and regular menstrual cycle.

Tabassum K. Belim, MD

Articles

Sublingual Dermoid Cyst

Obstructed Hemivagina and Ipsilateral Renal Agenesis (OHVIRA)