Dermatology: Practical and Conceptual


Image Letter | Dermatol Pract Concept. 2024;14(4):e2024264 1

Unraveling the Diagnostic Challenges and 
Complexities of Familial Gigantic Melanocytosis:  

A Rare Case
Ghosh Debaleena1, Chakraborty Disha1, Pal Shrayan1, De Abhishek1

1 Department of Dermatology, Calcutta National Medical College and Hospital

Citation: Debaleena G, Disha C, Shrayan P, Abhishek D Unraveling the Diagnostic Challenges and Complexities of Familial Gigantic 
Melanocytosis: A Rare Case. Dermatol Pract Concept. 2024;14(4):e2024264. DOI: https://doi.org/10.5826/dpc.1404a264

Accepted: June 6, 2024; Published: October 2024

Copyright: ©2024 Debaleena et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-
NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, 
distribution, and reproduction in any medium, provided the original authors and source are credited.

Funding: None.

Competing Interests: None.

Authorship: All authors have contributed significantly to this publication.

 Corresponding Author: Disha Chakraborty, Senior resident, Calcutta National Medical College and Hospital, D 629 Lake gardens 
Kolkata 700045 West Bengal, Tel: 91-9674074135. E-mail: docdishachaks@gmail.com

Case Presentation

A boy of 11 years, born of a consanguineous marriage, pre-

sented with silvery gray hair, which he has had since birth, 

along with insidious onset hyperpigmentation all over the 

body for the past 10 years. Similar changes were found in his 

maternal uncle. On cutaneous examination, diffuse hyper-

pigmentation was seen on the face, trunk, and lower limbs 

along with interspersed, raindrop-like hypopigmented mac-

ules (Figure 1A). Skin biopsy showed a heavily pigmented 

basal layer with giant melanocytes. Fontana Masson stain-

ing showed an increased number of large melanocytes along 

the basal layer, with slight melanin incontinence  (Figure 1, 

B and C). Trichogram revealed marked pigmentary di-

lution even in the normally pigmented hair of the patient 

when compared to hair from a normal individual along 

with irregular distribution of melanin along the hair shaft  

(Figure 1D). A diagnosis of familial gigantic melanocytosis 

(FGM) was made.

Teaching Point

Raising awareness about this seemingly benign disorder is 

crucial, as it can be easily diagnosed with a simple histopatho-

logical examination. This can help prevent unnecessary investi-

gations to differentiate it from similar-looking conditions such 

as Griscelli syndrome, Elejalde syndrome, and Chediak-Higashi 

syndrome, which are often linked to more serious neurological 

and hematological disorders [1,2]. In our case, although hair 

changes were present right at birth, the skin changes started 

appearing from four years of age. We also did a microscopic ex-

amination of both the normally pigmented hair and hypopig-

mented hair of the patient. Such unique features and findings 

in our case report might help to better understand the disease.



2 Image Letter | Dermatol Pract Concept. 2024;14(4):e2024264

References

1. El‐Darouti MA, Fawzi SA, Marzook SA, El‐Eishi NH,   

Abdel‐Halim MR, Soliman SA. Familial gigantic melanocyto-

sis. International journal of dermatology. 2005;44(12):1010-5. 

DOI: 10.1111/j.1365-4632.2005.02354.x.

2. Rambhia KD, Chowdhary KS, Rao GV, Khopkar US. Famil-

ial gigantic melanocytosis. Indian Journal of Dermatology,  

Venereology and Leprology. 2018;84:192. DOI:  10.4103/ijdvl 

.IJDVL_154_17.

Figure 1. (A) Diffuse hyperpigmentation with hypopigmented macules all over the body. (B) Giant me-

lanocytes in the basal layer of epidermis (H&E, ×40). (C) Larger, longer, heavily pigmented melanocytes 

(Fontana Masson, ×40). (D) A-Hair from a normal individual, B-Normally pigmented hair from a patient 

(unstained, ×40).