Pigmented Lesions Flashcards
Lesions with sunburst appearance?
- chondrosarcoma
- osteosarcoma
- melanotic neuroectodermal tumor
Melanophores
Melanophores are macrophages engulfing the extruded extra-cellular melanin (DOPA
negative).
Types of nevi
1- Keratotic nevi → white spongy nevus.
2- Vascular nevi → hemangioma and lymphangloma.
3- Pigmented nevi or melanotic nevi.
How are nevus cells different from melanocytes
Nevus cells differ from melanocytes in that they are usually smaller size, without dendrites, arranged in groups and are less metabolically active. Indistinct cell border Small uniform nucleus Moderate cytoplasm Melanin may be found
Site of aquired melanotic nevus
- Site:
- Extraoral:
Skin above waist.
ii. Intraoral:
Head & neck are common sites..
Uncommon in oral cavity.
Mainly in palate & buccal mucosa & gingiva.
Nodular melanoma
Dark pigmented elevations
Skin & mucous membrane.
Vertical growth pattern.
Superficial spreading melanoma
The most common type (70%). o Well defined, slightly elevated, pigmented patch.
In interscapular area in males & back of legs in females.
Radial growth phase for several years then vertical growth phase.
Lentigomaligna
Slowly expanding macule with irregular borders.
o Variety of colors as tan, brown, black or white.
Sun exposed skin of midface of old
age.
Radial growth phase 25 years, so prognosis is excellent until it enters the vertical growth phase leading to metastases and so poor
prognosis.
Acral lentigous
Most common type of oral melanoma.
• Orally in blacks in hard palate, gingiva, alveolar mucosa.
o Skin (palms of hands & soles of feet).
Radial then vertical growth pattern.
Melanoma Prognosis depends on
Prognosis depends on: o Histopathologic picture.
Depth of tumor invasion (Breslow depth & Clarck’s level).
Oral Lesions are usually of great thickness and so more advanced at the time of biopsy. o Poor prognosis of oral lesion is related to late recognition and difficulty of treatment in the oral
cavity. Clinical stage (metastasis):
Stage 1 → no metastasis (5 years survival rate 89% ).
- Stage II →→nodal metastasis (5 years survival rate 61%). “Stage III → disseminated tumor (5 years survival rate 0% ).
Overall 10 years survival rate 79%. Site → some sites have worse prognosis as:
Interscapular area of back. Posterior upper arm.
Posterior and lateral neck.
Scalp.
Oral lesions.
o Age → better prognosis for patients < 50 years. o Sex→ better prognosis in females.
Melanoma spread
Local → limited.
Lymphatic→→ to the regional lymph nodes.
Blood spread to the lung and then every other organ in the body. Melanin pigment may reach the blood (melanaemia) and excreted in urine
Ttt of melanoma
Treatment:
D Surgical removal with:
1 cm safety margin for early lesions.
3-5 cm safety margin for large invasive lesions.
o Removal of regional lymph nodes for lesions with histopathologic depth of invasion more than 1.24mm
o Radiotherapy & chemotherapy are ineffective.
Origin of melanotic neuroectodermal tumor
Origin:
o It arises from primitive pigment producing cells from neural crest. o The neural crest origin was confirmed by that almost all patients show an
elevated level of vannillymandelic acid (VMA) in urine. o Vanillylmandelic acid is the major urinary metabolite of nor epinephrine and epinephrine
Other names explained in melanotic neuroectodermal tumor
At one time the tumor was thought to arise from remnants of odontogenic tissues and named (melanoamelobastoma).
The term progonoma means a nodule or mass resulting from displacement of tissue which occurs in embryonic development.
Clinical of melanotic neuroectodermal tumor
- Age first year of life. 2. Sitemaxilla > mandible.
- Painless, darkly expanding pigmented mass
- Slow or rapid growth.
