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CASE REPORT
Year : 2020  |  Volume : 21  |  Issue : 3  |  Page : 197-199

Giant congenital melanocytic nevus with neurotized lesions mimicking neurofibromas – A rare presentation


Department of DVL, Government Medical College, Nizamabad, Telangana, India

Date of Submission20-Jan-2020
Date of Decision15-Mar-2020
Date of Acceptance26-Mar-2020
Date of Web Publication30-Jun-2020

Correspondence Address:
Dr. Sudharani Chintagunta
Plot No. #5, Jupiter Colony, Kakaguda, Kharkhana, Secunderabad, Telangana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijpd.IJPD_11_20

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  Abstract 


Giant congenital melanocytic nevus (GCMN) is a deeply pigmented lesion, often associated with hypertrichosis and multiple scattered satellite lesions. During infancy apart from textural changes, rapidly growing “proliferative nodules” mimicking melanoma can occur in the nevus. Areas of the nevus may be infiltrated by an overgrowth of fat or nerve tissue, so-called lipomatous or neurotized areas, respectively, common in larger nevi. We report a case of GCMN associated with multiple neurotized areas mimicking large neurofibromas, a rare phenomenon.

Keywords: Congenital giant melanocytic nevus, neurofibromas, neurotization


How to cite this article:
Chintagunta S, Jaju P, Sankineni P. Giant congenital melanocytic nevus with neurotized lesions mimicking neurofibromas – A rare presentation. Indian J Paediatr Dermatol 2020;21:197-9

How to cite this URL:
Chintagunta S, Jaju P, Sankineni P. Giant congenital melanocytic nevus with neurotized lesions mimicking neurofibromas – A rare presentation. Indian J Paediatr Dermatol [serial online] 2020 [cited 2020 Aug 5];21:197-9. Available from: http://www.ijpd.in/text.asp?2020/21/3/197/288482




  Introduction Top


Congenital melanocytic nevus (CMN) is a benign neoplasm composed of nevomelanocytes. Giant CMN (GCMN) is a rare condition, defined as melanocytic nevi which are >20 cms in dimension.[1] They are deeply pigmented, covered with a moderate growth of hair, and often associated with multiple scattered satellite lesions. Despite its rarity, it is considered important because it may be associated with complications such as malignant melanoma and malignant neuroectodermal tumors and also has a major psychosocial impact on the patient due to its unsightly appearance.[2]

Here, we present a case of GCMN associated with multiple large tumor-like lesions resembling neurofibromas.


  Case Report Top


A 16-year-old female presented with GCMN on the trunk and thigh associated with hypertrichosis since birth with a history of large asymptomatic swellings over the pigmented area for 4 years which gradually increased in size.

Cutaneous examination showed an extensive darkly pigmented nevus covering the trunk, pubic region, and lower extremities. There were darkly pigmented lesions of variable sizes, more than 50 in number, present all over the body including face [Figure 1]. There were five large subcutaneous swellings present over the pubic region (8x 8cms), anterior and posterior aspects of left lumbar region (30x20cms and 10x24cms respectively) and two swellings on the buttock (8x8cms and 8x10cms respectively) [Figure 2] and [Figure 3]. All the swellings were soft to firm in consistency, nontender, and freely mobile. General and systemic examination was normal.
Figure 1: Clinical image showing multiple melanocytic nevi on the face and neck

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Figure 2: Giant bathing trunk melanocytic nevus with large, protuberant skin lesions mimicking neurofibromas over the trunk, left flank, and pubic region

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Figure 3: Similar lesions on the back

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Two biopsies were taken: one from pigmented patch and other from tumorous growth. A diagnosis of GCMN with neurotization was made.

The histopathological examination revealed stratified squamous epithelium with subepithelial atypical pigmented nevus cells in sheets with intracellular and extracellular melanin pigment cells seen infiltrating deep stroma [Figure 4] and [Figure 5].
Figure 4: (H and E, × 10) Nests of nevomelanocytes in the basal layer of the epidermis and deeper dermis

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Figure 5: (H and E, × 20) Melanocytes in the basal layer of epidermis are plump, rounded in shape with multiple nests of nevomelanocytes in the deeper dermis

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On clinicopathological correlation, a diagnosis of CMN with neurotization was made.


  Discussion Top


GCMN is a rare condition with an incidence of 1:20,000 newborns with a slightly higher prevalence in females.[3] Along with the growth of the child, GCMN can undergo further darkening of the lesions through adolescence, increase in surface roughness, appearance of nodules, and hypertrichosis.[4]

These rapidly growing, proliferative nodules within CMN may mimic melanomas or neurofibromas. These nodules in the nevus may also correspond to the proliferation of neuroid tissue elements.

Areas of the nevus may be infiltrated by overgrowths of fatty or nerve tissue, so-called lipomatous or neurotized areas, respectively, which is most often in larger CMN.

Clinically, neurotized melanocytic nevi and neurofibromas look similar, histologically distinct from each other.

Other tumors, benign or malignant, can occur in patients with GCMN. In the group of benign tumors, lipomas and benign schwannomas can occur. Among tumors with some degree of malignancy, the following can be identified: malignant cellular blue nevus, minimal deviation melanomas, sarcomas, malignant schwannomas, liposarcomas, and rarely sarcomas.[5]

GCMN also presents a variety of histological elements. In the neural subtype, there are areas of neuroid tissue differentiation, and the lesion may resemble a neurofibroma. The diversity of histological elements in GCMN could be explained by the fact that these lesions originate from a pluripotent stem cell, which can differentiate into multiple cell types.

The term neurotization refers to the resemblance of some melanocytic cells to peripheral nerve sheath cells. Melanocytic cells located in the epidermis and upper dermis, epithelioid or type A cells, have a rounded appearance. In the deeper dermal component of the nevus, cells may have a spindle-shaped appearance and resemble peripheral nerve sheath cells; these have been termed Type C-cells. Nevus cells in the mid-dermis, which are small and round in appearance, are termed B-cells.[6] It has been suggested that immunohistochemical markers can be used to differentiate between neurofibromas and neuroid nevi reliably. Nevus cells of all types will stain with S-100 but not with Leu-7 (CD57), myelin basic protein (MBP), or glial fibrillary acidic protein (GFAP), whereas neurofibromas stain with Leu-7, MBP, and GFAP as well as with S-100.[6]

All of the melanocytic nevi showed Melan-A staining within the neurotized areas, with most of the areas staining strongly positive, whereas all the neurofibromas were completely absent of Melan-A stain.

GCMN are prone to develop nodular proliferation in neonatal age, but this case developed large tumor-like growth in adolescence. Clinically, these lesions resemble neurofibromas, and histologically, they were consistent with neurotization of the nevus.

Hence, all neurofibroma-like lesions detected clinically over CMN are not real neurofibromas. Melan-A immunohistochemical staining is helpful in differentiating neurotized melanocytic nevi from neurofibromas, which was not done in this case due to nonavailability in our institute.


  Conclusion Top


This is a rare presentation of unusually large benign tumors arising in adolescence clinically mimicking neurofibromas. Hence, a conscious approach for such cases is needed to differentiate pigmented neurofibroma, and neurotized melanocytic nevus may pose a diagnostic challenge.

Declaration of patient consent

Author certify that they have obtained all appropriate patient consent forms. In the form the patients/parents have given their images and other clinical informations to be reported in the journal. The patients & parents understand that their/their children's names and initials will not be published and due efforts will be made to conceal their identity.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Arneja JS, Gosain AK. Giant congenital melanocytic nevi. Plast Reconstr Surg 2007;120:26e-40e.  Back to cited text no. 1
    
2.
Gach JE, Carr RA, Charles-Holmes R, Harris S. Multiple congenital melanocytic naevi presenting with neurofibroma-like lesions complicated by malignant melanoma. Clin Exp Dermatol 2004;29:473-6.  Back to cited text no. 2
    
3.
Castilla EE, da Graça Dutra M, Orioli-Parreiras IM. Epidemiology of congenital pigmented naevi: I. Incidence rates and relative frequencies. Br J Dermatol 1981;104:307-15.  Back to cited text no. 3
    
4.
Na CH, Song IG, Chung BS, Shin BS. Case of pigmented neurofibroma with hypertrichosis with no association to neurofibromatosis. J Dermatol 2009;36:541-4.  Back to cited text no. 4
    
5.
Bevona C, Goggins W, Quinn T, Fullerton J, Tsao H. Cutaneous melanomas associated with nevi. Arch Dermatol 2003;139:1620-4.  Back to cited text no. 5
    
6.
Gray MH, Smoller BR, McNutt NS, Hsu A. Neurofibromas and neurotized melanocytic nevi are immunohistochemically distinct neoplasms. Am J Dermatopathol 1990;12:234-41.  Back to cited text no. 6
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

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