Adnexal neoplasms Flashcards
What is a hamartoma?
A benign proliferations of native cellular elements in abnormal proportions.
e.g sebaceous naevus
What is a hair follicle naevus? What are the clinical features? and the histology features?
A congenital hamartoma involving abnormal or increased number of hair follicles.
Clinical
- small skin coloured papule
- fine hairs protruding
- normally on the face (near the ear)
Histopathology
- Domed surface
- Increased Vellus hair follicles
No treatment is required.
What is a trichofolliculoma?
A follicular hamartoma with structures emanating from a central dilated follicular infundibulum
Clinical:
○ Small papule or nodule
○ typically on the face, scalp, or upper trunk.
○ May have a central punctum
○ May have a small tuft of lightly pigmented hairs
Histology:
○ Central cystic space with infundibular cornification and orthokeratin.
○ Vellus follicles radiating from the cyst.
- Surrounded by vascularized fibrous stroma.
What is a fibrofolliculoma or Trichodiscoma? and how does it present?
Adnexal hamartoma with follicular epithelial and mesenchymal elements
Small, skin-colored to hypopigmented papules (normally multiple)
Commonly on head, neck, upper trunk.
What syndrome should you consider in a patient with multiple fibrofolliculomas?
What are the features of this syndrome?
Birt Hogg Dube syndrome
Rare autosomal dominant condition
(FLCN gene)
Feature:
- multiple fibrofolliculomas / trichodiscomas
- angiofibromas and skin tags
- Benigns cysts in the lungs (leading to pneumothorax)
- Benign renal cysts, Renal cell carcinoma
- ?? cutaneous melanoma (not proven)
What are the histology features of fibrofolliculomas?
Strands of basaloid cells emanate from a folliculosebaceous unit
Form a mitt-like configuration encasing delicate fibrous stroma
What is a sebaceous naevus? what is the natural history?
A harmatoma of the sebaceous unit.
Present as a raised yellow subtle lesion at birth, along the lines of Blashko
become more verrucous in adolescents
Risk of developing benign neoplasms (tricholemmoma, syringocystadenoma etc) and malignancy (<1%)
What secondary neoplasms may occur in a sebaceous naevus?
Trichoblastoma: (most frequent)
Syringocystadenoma papilliferum
Tricholemmoma
Desmoplastic tricholemmoma
Sebaceous adenoma
Apocrine adenoma
Poroma
Rare (<1%)
Sebaceous carcinoma Apocrine carcinoma
BCC
Treatment of a sebaceous naevus?
Low risk of carcinoma but higher risk for secondary benign neoplasms.
Conservative excision during late childhood recommended (before verrucous changes develop).
Facial lesions may be excised early; scalp lesions are harder to monitor clinically.
What is Trichoepithelioma or Trichoblastoma?
Benign neoplasms with follicular germinative differentiation.
(trichoepithelioma is a variant of a trichoblastoma)
How do trichoblastomas present?
skin-colored papules or nodules
typically on the face or upper trunk
(commonly on the nose!)
What is epithelioma adenoides cysticum?
Describes multiple trichblastomas on the face
What is the name for multiple trichblastomas on the face?
epithelioma adenoides cysticum
What are the histological features of a trichoblastoma?
Well circumscribed
Symmetrical
Tumour of basaloid cells
Minimal / no cytological atypia
No cleating between cells and stroma
Papillary mesenchymal bodies
What are the histological features of a desmoplastic Trichoepithlioma?
Cords of basaloid cells
Often only two cells wide
arrayed interstitially amongst collagen bundles
Often in the upper 2/3 of the dermis
Relatively well circumscribed
Small cystic foci of isthmus or infundibular keratinisation may be present
How should trichoblastomas be treated?
Benign lesions - can be left.
If multiple - risk of BCC development.
- Excision
- CO2 ablative laser
- electrocautery
- sirolimus
- imiquimod
What histology stain can be used to differentiate trichoepithelioma and BCC?
CK20 negative favours BCC
PHLDA1 negative favours BCC
How do desmoplastic trichoepitheliomas present?
Firm skin-colored to erythematous annular plaque with a central dell
Most are solitary
Multiplicity is rare.
Commonly on the cheek,
F >M
What is a pilomatricoma? and how does it present?
benign follicular matrical neoplasm that is characterized by matrical cornification (keritinisation)
Solitary, firm, skin-colored, yellow, or bluish papules or nodules.
Children >Adults
Head and neck > other hair bearing areas
Pilomatricomas are seen in what syndromes?
Myotonic dystrophy,
Turner syndrome,
Rubinstein–Taybi syndrome,
Gardner syndrome = FAP (if cystic)
What is the histology of a pilomatricoma?
A Cyst with central matircal cornification
Cyst wall = basaloid cells
Abrupt transition to central eosinophilic material
Loss of the nucleus = shadow or ghost cells
NB: can have lots of mitoses
In late lesions;
- can have calcification / ossification
- fibrosis granulomatous reaction
Treatment of a pilomatricoma
Benign - although excision to prevent recurrence
How to pilomatricomas differ histologically to pilomatrical carcinomas?
Same a pilomatricoma (basaloid cells, ghost cells, mitoses) but:
Nuclear Pleomorphism
Poorly circumscribed with a infiltrative configuration
Tumour necrosis
Ddx of a pilomatrical carcinoma?
BCC
Pilomatricoma
SCC
