there had been no pain or dysphonia but a bothersome sensation related to progressive surface roughness that prompted her to seek care .
she was otherwise healthy ; a small congenital melanocytic nevus affecting the right inner thigh had been excised during early childhood . on examination
, there was no palpable cervical lymphadenopathy . a well - demarcated , circular plaque ( 1.21.10.3 cm ) with a slight pebbled texture affected the left posterior hard palate . while predominantly erythematous , there was scattered light brown pigmentation ( figure 1 ) .
figure 1initial presentation of a non - homogenous brown - pigmented palatal plaque . 
  initial presentation of a non - homogenous brown - pigmented palatal plaque .
the underlying stroma contained sheets of nevus cells ( figure 2 ) exhibiting maturation and extending deep into the lamina propria and around minor salivary ducts ( figure 3 ) , nerves and blood vessels .
cells diffusely stained with melana ( figure 5 ) and ki-67 suggested a low proliferative index . only the superficial cells stained with hmb-45 ( figure 6 ) . 

figure 2papillomatous oral squamous epithelium and sheets of nevus cells extending deep within the lamina propria ( h+e , 4 ) . 
 
papillomatous oral squamous epithelium and sheets of nevus cells extending deep within the lamina propria ( h+e , 4 ) . 

figure 4scant melanin pigmentation was seen only in superficial nevus cells ( h+e , 20 ) . 
 
scant melanin pigmentation was seen only in superficial nevus cells ( h+e , 20 ) . 

figure 5diffuse staining of nevus cells with melana . 
  diffuse staining of nevus cells with melana . 

melanocytic nevi are separated into acquired and congenital subtypes with the latter identified at birth . the palate is not easily visualized , however , which may explain delayed identification . while it is recognized that parental history may not be accurate , there was certainty of identification during early infancy .
the larger size was suggestive of a congenital nevus as acquired nevi are usually less than 6 mm in diameter .
congenital nevi may have a papular , pebbly or verrucous surface as well as hypopigmented areas .
histologically , a congenital pattern was characterized by a diffuse infiltration of nevus cells extending around blood vessels , nerves , salivary ducts as well as between collagen bundles .
nevus cells may exist and proliferation in diverse anatomic locations as evidenced by identification of aggregates in the parenchyma of lymph nodes .
oral melanocytic nevi are uncommon , and to the best of these authors knowledge , only three well - documented cases of intraoral congenital melanocytic nevi have been reported in the english literature , ( table 1 ) .
other mucosal sites are also uncommonly affected with rare reports of conjunctival or genital congenital nevi .
characteristics of reported oral congenital melanocytic nevi classification of congenital melanocytic nevi is by size : small ( < 1.5 cm ) , medium ( 1.5 to 19.9 cm ) and large or giant ( > 20 cm ) .
the primary concern is malignant transformation and there is general agreement that the risk increases with the size . while a clear risk exists for larger lesions , such an association is controversial with small congenital nevi .
identified histologic features of congenital nevi in 8.1% of melanoma specimens . in another study , a melanoma risk of 2.64.9% was estimated for persons with small congenital nevi and it was concluded that small congenital nevi may represent precursors for at least some cases of cutaneous melanoma .
there is general agreement that the larger the congenital nevi the more likely the need for excision . for small congenital nevi
, management may be either excision or observation but there exists no clear consensus or guidelines .
excision seems reasonable as in most cases one would expect minimal surgical morbidity and excision facilitates comprehensive histologic sampling to exclude melanoma , and presumably , may prevent malignant transformation . from the patient 's perspective , as was the case with this patient failing to attend post - surgical assessment , excision may potentially mitigate the necessity for long - term observation .
ultimately , decisions require individualization with consideration of the size , anatomic restrictions as well as patient factors such as co - morbidities and ability to attend observation .
 oral pigmented lesions are uncommon and congenital melanocytic nevi are especially rare . 
 we report a case of a patient with multiple congenital melanocytic nevi including a palatal lesion . 
 this is reported to add to the scant literature that exists on this subject . 
 prognosis and management are discussed . 
Case Report
Discussion