In the papillary and upper reticular dermis, dendritic melanocytes are present and surrounded by fibrous sheaths (which are not present in other dermal melanocytosis, such as blue nevus
or mongolian spots).
Combined histologic patterns of a blue nevus
, spindle and Spitz nevus, or a deep penetrating nevus were identified in 40% of CMN.
From 4-year-old the child was gradually found to have multiple blue nevus
in the tongue and the skins on the sole of left foot right forearm neck and genitalia etc (Fig.
Histopathologically, three patterns may be encountered: A compound or an intra-dermal nevus, a neural nevus, and a blue nevus
144) Just as HMB-45 does not label intradermal nevi, Biddle et al (178) found that an intranodal nevus is negative for HMB-45, unless it is a nodal blue nevus
Young LC, Van Dyke GS, Lipton S, Binder SW: Poliosis overlying a nevus with blue nevus
Lesions included adnexal neoplasm, ameloblastic fibro-odontoma, basal cell carcinoma, benign fibrous histiocytoma, blue nevus
, chondrosarcoma, compound nevus, epithelioma adenoides cysticum, esthesioneuroblastoma, Ewing sarcoma, fibrosarcoma, giant cell granuloma, granulocytic sarcoma, hemangioma, hemangiopericytoma, Langerhans cell histiocytosis, lymphangioma, lymphoma, melanoma, neuroblastoma, neurofibroma, ossifying osteofibroma, osteochondroma, osteosarcoma, port wine stain, rhabdomyosarcoma, Spitz nevus, and xanthogranuloma.
The features of NCH overlap with blue nevus
both clinically and histopathologically.
Certain lesions are said to be precursor lesions of melanoma, including the common acquired nevus, dysplastic nevus, congenital nevus and cellular blue nevus
On the other hand, ZEMBOWICZ & MIHM (2004) considers that most of the histological variants recently introduced in the medical literature such as amelanotic/hypomelanotic blue naevus, amelanotic cellular blue naevus, epithelioid blue nevus
, compound blue naevus, atypical blue naevus, pilar neurocristic hamartoma, blue naevus-like metastatic melanoma, pigmented epithelioid melanocytoma and cutaneous neurocristic harmatoma/ malignant neurocristic tumors could be classified as traditional categories of dendritic melanocytic proliferations.
Heterotopic inclusions Lymph nodes commonly involved Breast tissue Axillary Aggregate of nevus cells Axillary Blue nevus
Axillary Squamous epithelium Cervical and peripancreatic Salivary gland tissue Cervical Thyroid follicles Cervical Decidual tissue Pelvic Epithelium of paramesonephricus type Pelvic Intestinal glands Mesenteric Mesothelial cells Mediastinal and retroperitoneal Pantanowitz & Upton, 2003.
Some entities that can mimic melanoma include a halo nevus, solar lentigo, traumatized blue nevus
, seborrheic keratosis, pigmented basal cell carcinoma, pigmented Bowen's disease, pigmented squamous cell carcinoma, and thrombosed angioma.