Dermoid cysts are cysts lined with squamous epithelium that contain skin adnexa such as sweat glands, sebaceous glands, and hair follicles. There are several types of dermoid cysts including congenital dermoid cysts that form along embryonic fusion lines and can cause bony defects, implantation dermoid cysts that form after skin implantation injuries, and teratomatous dermoid cysts containing tissues from all germ layers. Dermoid cysts typically present as slow-growing, painless swellings and are diagnosed based on location and imaging findings showing cystic masses sometimes eroding adjacent bone. Excision is the treatment.

1. DERMOID CYST

2.  Cyst lined by squamous epithelium
containing desquamated cells
 CONTENTS
mixture of sweat, sebum, desquamated
epithelial cells, hair

3. CLINICAL TYPES
 CONGENITAL / SEQUESTRATION DERMOID
SITE: along lines of embryonic fusion (midline
of body or face)
FORMATION: dermal cells sequestrated in
subcutaneous plane > proliferate & liquify >
cyst > grows & indents mesoderm(future
bone) > bony defects

4.  MEDIAL NASAL DERMOID CYST (root of
nose at fusion lines of frontal process)
 EXTERNAL AND INTERNAL ANGULAR
DERMOID ( fusion line of frontonasal and
maxillary processes)
 SUBLINGUAL DERMOID
 PRE –AURICULAR DERMOID
 POST AURICULAR DERMOID

6. CLINICAL FEATURES
 Manifests in childhood or adolescence
 Typically a painless slow growing swelling
 Soft, cystic, fluctuant, yield to pressure of
finger and will not slip away
 Transillumination negative
 Putty in consistency
 No impulse on coughing
 Underlying bony defect – clue to diagnosis
 Location along line of fusion

8. OTHER TYPES
 IMPLANTATION DERMOID
> in women, tailors, agriculturists who
sustain repeated minor injuries
> sharp injury- epidermal cells implanted in
subcutaneous plane- dermoid cyst
> fingers, palm, sole of foot
> hard in consistency ( skin is thick)

9.  TERATOMATOUS DERMOID
> arise from totipotent cells
> ectodermal, mesodermal, endodermal
elements
> ovary, testis,retroperitoneum, mediastinum

11.  TUBULO-EMBRYONIC DERMOID
> from ectodermal tubes
> thyroglossal cyst, post- anal dermoid

12. INVESTIGATIONS
 BLOOD – TC, DC,Hb,ESR
 URINE Examination
 FNAC-
 X ray- subjacent bone eroded by dermoid
 Ultrasonography- mass cystic/ solid
 CT scan- size , shape , local spread

13. TREATMENT
 Excision of the cyst
Mass shown ( implantation dermoid) Incision marked

14. Incision started ( cyst contents leaking) cyst being removed

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