Head and Neck, Skin and Soft Tissue Flashcards
What are the differentials of a neck lump based on anatomy?
Midline
- Thyroglossal cyst
- Dermoid cyst
- Thyroid swelling (benign or malignant)
Anterior triangle
- Lymphadenopathy (infective, inflammatory, cancer (primary or secondary)
- Branchial cyst
- Carotid body tumour
- Salivary gland pathology (saliadenitis, salialithiasis, ranula, retention cyst, cancer)
Posterior triangle
- Lymphadenopathy (infective, inflammatory, cancer (primary or secondary)
- Cystic hygroma
- Pharyngeal pouch
- Cervical rib
Common to all regions - skin and subcutaneous lesions (lipoma, epidermoid cyst)
What are the differentials for neck lumps based on congenital versus acquired?
Congenital (20%)
- Branchial cleft cyst
- Thyroglossal duct cyst
- Dermoid cyst
- Vascular tumours and and malformations (haemangioma, lymphangioma, cystic hygroma).
Acquired (80%)
**Benign **
Skin and subcutaneous (lipoma, sebaceous cyst)
Lymphadenopathy (reactive, infective, inflammatory)
Thyroid (MNG, nodular thyroiditis, cyst, follicular adenoma)
Salivary gland (retention cyst, ranula, sialolithiasis, sialadenitis, adenoma)
Pharyngeal pouch
Vascular (carotid body tumour)
Neuronal (neurofibroma, schwannoma)
**Malignant **
Primary - thyroid, salivary glands, lymphoma, sarcoma
Secondary - SCC, melanoma, thyroid/salivary glands, infraclavicular malignancy
What are the contents of the posterior triangle?
**Vessels **- third part of subclavian artery, suprascapular and transverse cervical branches of thyrocervical trunk, external jugular vein, lymph nodes.
Nerves - accessory nerves, brachial plexus trunks, fibers of the cervical plexus
What are the contents of the anterior triangle?
Muscles - thyrohyoid, sternothyroid, sternohyoid
Organs - thyroid gland, parathyroid gland, larynx, trachea, oesophagus, submandibular gland, larynx and trachea
Arteries - superior and inferior thyroid a, common carotid, external carotid, internal carotod a, facial, submental and lingual
Veins - anterior jugular veins, internal jugular, common facial, lingual, superior thyroid, middle thyroid, facial veins, submental, lingual veins.
Nerves - vagus nerve, hypoglossal nerve, part of sympathetic trunk, mylohyoid nerve
What are the differentials for lymphadenopathy?
**Benign **
Infectious
- Viral
URTIs - adenovirus, rhinovirus, enterovirus
EBV
HSV, CMV, mumps, measles, rubella, HIV
- Bacterial
STaph, strep, toxoplasmosis, brucellosis, cat sratch disease
Mycobacterial infections (TB)
Inflammatory
- Sarcoidosis
- Amyloidosis
- Kawasaki disease
Autoimmune
- SLE
- RA
Medications
- Phenytoin, allopurinol and captopril
Malignant
Primary
- lymphoma
Secondary
- Metastasis
What is a brachial cleft cyst?
A congenital epithelial cyst that arises from the lateral aspect of the neck usually due to failure of obliteration/involution of branchial cleft in embryonic development
What is the anatomical pathway of the second brachial cleft cyst?
Anterior border of upper 1/3 SCM, deep to platysma, between external and internal carotid arteries, superficial to hypoglossal and glossopharyngeal nerves and ends in tonsillar fossa.
What is a carotid body tumour?
This is a paraganglioma of the carotid body derived from chemoreceptor cells
This is the most common head and neck paraganglioma (65%) with 5% bilateral and 5% malignant
What is Merkel cell carcinoma?
Rare aggressive cutaneous neuroendocrine malignancy thought to arise from Merkel cells in the epidermis.
Most common site is the head and neck region
What are the 2 main theories for Merkel cell pathogenesis?
Traditional -> merkel cells that are located in the basal layer of the epidermis and hair follicles are associated with the mechanoreceptors/sensory neurites in dermal papillae (BUT majority are intradermal as opposed to epidermal)
Alternative -> Arise from totipotential stem cell that acquires neuroendocrine features during malignant transformation
What are the risk factors asscociated with Merkels cell carcinoma ?
A - asymptomatic
E - expanding rapidly
I - immunosuppressed
O - older than 50
U - UV radiation exposure
Also , associated with merkel cell polyomavirus
What are the management principles of Merkel cell carcinoma?
Surgical excision
- 1-2cm margin (vertical growth, with tendency to invade deep margin)
Radiotherapy - primary radiotherapy for patients who are not surgical candidates
Lymph nodes - only predictive factor of LN mets is tumour size (30% if greater than 1cm)
-> SLNBx - in all patients with negative nodes. For head and neck, variable. If not undergoing SLNBx, radiotherapy. If SLNBx positive, stage patient
-> Regional LND - clincally involved nodes or in +ve SNLBx. Adjuvant RT given. (primary RTx to LNs is an alternative).
Adjuvant radiotherapy post op Ix
- Tumour > 1 cm
- Head and neck primary
- Positive or close resection margins
- LVI, multiple LN involvement
- extracapsular extension of LNs
- immunosuppressed
Systemic therapy
- PD1 inhibitor (pembrolizumab)
What are the prognostic factors for melanoma?
Tumour thickness
- > 2mm significantly worse prognosis
Ulceration
Mitotic rate
Lymphatic involvement
Patient related:
- Age (older worse)
- Gender (male worse)
- Site (head, neck, trunk worse)
- Raised LDH
What are the adjuvant treatment options for melanoma?
Dependent on patient factors (age, fitness, wishes) and disease factors (node +ve, mets, high risk node -ve
Immunotherapy
- PD-1 receptor (pembrolizumab) - blocks the activity of PD-1 on tumour cells ( PD-1 prevents T cells from recognising and attacking inflammatory and tumour cells). Therefore increasing the immune systems ability to attack melanoma cells.
- CTLA-4 inhibitors (ipilimumab) - present on T cells -> binding to this receptor allows the T cell to remain activated against melanoma.
Targeted therapy (if BRAF mutation present (50% of the time))
- BRAF inhibitors (selectively inhibits mutant BRAF kinase)
- MEK inhibitors
Radiotherapy
- Primary site indications (cant resect, recurrence, positive margins), desmoplastic/neutrotropic features, extensive lymphatic invasion, satellitosis.
- Regional node basins - based on high risk factors for post lymphadenectomy regional recurrence. Number (>1 parotid, >2 cervical, >3 groin nodes), size >3cm neck or axillla or >4cm in groin, extranodal spread, recurrence, unresectable nodal disease.
- Palliative care for brain or spinal mets
What wide local excision margins would you take for melanoma based on the Breslow thickness?
- T1 <1mm = 1cm
- T2 1-2 mm = 1-2cm Consider narrower for cosemetically or functionally sensitive areas
- T3/4 >2mm = 2cm
