Head and neck
Spencer W. Beasley, John Hutson, Mark Stringer, Sebastian K. King, Warwick J. Teague in Paediatric Surgical Diagnosis, 2018
There are four main causes of a midline cervical swelling in childhood, of which thyroglossal cyst is the most frequent. The other causes are infected submental lymph nodes, dermoid cyst and the rare ectopic thyroid. The site of the lump, the degree of movement on swallowing and protrusion of the tongue, and whether the lump is transilluminable usually enable the diagnosis to be made on clinical grounds. Examination includes inspection of the inside of the mouth: the cause of submental nodal infection is usually severe untreated dental caries. A dermoid cyst is mobile in the subcutaneous plane and may have a creamy hue through the skin. Thyroglossal cysts and dermoid cysts are best excised; the thyroglossal cyst and its tract should be removed in their entirety, which involves excision of the middle third of the hyoid bone and a suprahyoid core of tongue muscles. If an ectopic thyroid is suspected, the location of all functioning thyroid tissue can be demonstrated on a radionucleide scan of the neck.
Benign conditions of the ovary and pelvis
Helen Bickerstaff, Louise C Kenny in Gynaecology, 2017
These are the most common ovarian tumours in young women aged 20–40 years, accounting for more than 50% of ovarian tumours in this age group with a peak incidence in the early 20s. The most common form of benign germ cell tumour is the mature dermoid cyst (cystic teratoma), which contains fully differentiated tissue types derived from all three embryonic germ cell layers (mesenchymal, epithelial and stroma). Hair, teeth, fat, skin, muscle, cartilage, bone and endocrine tissue are frequently present. Up to 10% of dermoid cysts are bilateral. The risk of malignant transformation is rare (<2%), usually occurring in women over 40 years. Diagnosis is usually confirmed with a pelvic USS (Figure 11.1C) and because of the high fat content present in dermoid cysts, MRI may also be useful where there is uncertainty. In general, ovarian cystectomy is indicated because spontaneous resolution is unlikely. Surgery is especially indicated if the dermoid cyst is symptomatic (Figure 11.2), is more than 5 cm in diameter or is enlarging. Cystectomy will prevent ovarian torsion and provide tissue for histological analysis.
SBA Answers and Explanations
Vivian A. Elwell, Jonathan M. Fishman, Rajat Chowdhury in SBAs for the MRCS Part A, 2018
A dermoid cyst is a subcutaneous lump that develops mostly in the midline along the lines of fusion in the face and neck. It is a result of the inclusion of epidermal cells deep to the skin, which can be congenital or secondary to trauma.
A superficial nasal dermoid cyst excised through a novel horizontal zig-zag incision in a 49-year-old man
Published in Acta Oto-Laryngologica Case Reports, 2020
Jeremy Wales, Babak Alinasab, Ola Fridman-Bengtsson
A dermoid cyst is classically described as a cyst that is lined with stratified squamous epithelium and may contain normal constituents of the epithelium, including hair and sebaceous glands [7]. There are currently two theories to explain the pathogenesis of NDCs, the prenansal space theory and the cutaneous theory, as discussed by Moses et al. [2]. The prenasal space theory, as originally proposed by Pratt in 1965 [8], suggests that failure of obliteration of the prenasal space, in front of the nasal cartilage, during development is responsible. This allows a fetal dural diverticulum to form that is in contact with the skin, resulting in a dermal cyst with intracranial extension. However, a competing theory, the cutaneous theory, has been described. This relies on the fact that the nasal capsule has an outer layer of skin and an inner mucous membrane. The skin dissociates from the cartilage at 3 months as the bony nasal structure ossifies. Ectodermal fragments may remain attached to the cartilage resulting in a dermoid cyst.
A giant dermoid cyst of the orbit
Published in Orbit, 2019
Bipasha Mukherjee, Akruti Desai
Computed tomography (CT) of brain and orbit revealed a heterogenous, mixed solid and cystic lesion completely filling the left orbit. A densely calcified area was seen anterior to the lesion. No globe structures, extraocular muscles, or optic nerve could be identified (Figure 2A). Magnetic resonance imaging showed a slightly thickened optic nerve posterior to the lesion, but the intracanalicular and intracranial part of the nerve was noted to be thin (Figure 2B). In view of these findings, the possibility of a teratoma, lymphangioma, or optic nerve glioma was considered. Hematological investigations were normal. The patient underwent a left orbital mass excision biopsy. Intraoperatively, a superiorly displaced small globe-like structure was found (Figure 3). A lateral orbital wall outfracture was performed to aid separation and in-toto removal of the mass (Figure 4). Histopathological examination of the lesion showed a large lobular cystic mass 41 × 51 mm with a small eyeball on top measuring 22 × 21 mm. The tumor was encapsulated lined by keratinizing stratified squamous epithelium with a thickened wall which contained inflammatory cells. The cystic areas were filled with blood and eosinophilic material (Figure 5). There was no evidence of any malignant cells. A diagnosis of a giant dermoid cyst was made from the above findings. Socket reconstruction is planned at a later date. The patient is awaited for follow-up.
Paediatric orbital conjunctival epithelial cyst with positive asialotransferrin
Published in Orbit, 2020
Rukaiya Malik, James English, Thomas G. Hardy
A 15-month-old girl presented with her parents with left proptosis and a one year history of increasing hypermetropia and hyperglobus. She had no past medical history, but a past ocular history of physiological anisocoria at 3 months’ age (cocaine test negative for Horner’s syndrome). At presentation, the patient had left eye proptosis and strabismus with hypertropia, a normal dilated fundal examination and a best-corrected visual acuity (BCVA) was 6/9.6 in the right eye and 6/12 in the left eye. Her MRI scan showed a moderate to large cystic lesion in the inferolateral left orbit in very close proximity to the optic nerve, displacing the inferior rectus and lateral rectus (Figures 1 & 2). Adjacent to the orbital lesion, an anatomically separate CSF filled anomaly was seen in the left middle cranial fossa, of similar iso-intensity to the orbital lesion (Figure 3). The lesion was suspected to be a dermoid cyst. Hence, the patient was booked for excisional biopsy via a transconjunctival approach.