Medires Publishers - Article

Abstract

Colloid milium is a rare, degenerative skin disorder characterized by yellowish-brown, dome-shaped papules and plaques, usually on sun-exposed areas. It is more common in males and typically presents as asymptomatic, symmetrical lesions. Our patient, a 50-year-old male with Fitzpatrick skin type 4 and universal vitiligo developed such lesions over three years. Histopathology revealed hyperkeratosis, eosinophilic nodular collections with fissures in the dermis, and elastotic fiber clumping, confirming colloid milium. Treatment options are limited, focusing on UV protection, topical retinoids, dermabrasion, cryotherapy, diathermy, and Er-YAG laser.

Introduction

Colloid Milium is a rare degenerative skin disorder which is characterized by multiple, 1-4 mm translucent, dome-shaped, yellowish brown papules and plaques on sun-exposed areas of skin. It is commonly seen in males than in females [1].

 It has been classified into four types namely, 1) Juvenile type, arising from degenerating keratinocytes, 2) Adult type, from degenerating elastic fibres, 3) Pigmented type, due to detrimental effects of petroleum products and hydroquinone, and 4) Nodular colloid, developing in old age [2].

The Ultraviolet radiations (UV) in sunlight are believed to play a major role in its pathogenesis. These break down elastin fibres resulting in an accumulation of proteins and/or fibroblast products in the dermis. Trauma and phenols in gas oil have also shown contributory effects [3].

Case report

A 50-year-old male from Delhi, having Fitzpatrick skin type 4 disorder and universal vitiligo complained of persistent, asymptomatic and symmetrical skin lesions on the hands which increased in number over a period of three years. He had no history of other medical illnesses and did not receive any treatment including photosensitizing medications. Family history was negative for similar lesions. Patient had a history of chronic sun exposure owing to his profession as an auto rickshaw driver.

Physical examination revealed multiple asymptomatic small pinhead sized, firm, round, skin-coloured, waxy papules located exclusively and symmetrically on the dorsum of both wrists and hands. Signs of photoaging were noted on the surrounding skin with erythema and telangiectasia. (Figure 1a).  

Dry, non-contact, polarised dermoscopy at 10x magnification using DermLite DL5 showed yellowish brown globules with dark brown reticular structures in its centre suggestive of septae along with small linear vessels in some (Figure 1b).

Histopathology revealed a hyperkeratotic epidermis with underlying nodular masses of homogenous eosinophilic material having fissures and clefts in upper dermis. Additionally, a thin grenz zone of uninvolved collagen with clumping of elastotic fibres was seen. These two characteristic features led to a diagnosis of colloid milium. (Figure 2)

Fig 1: 50-year-old man with Fitzpatrick skin type 4 disorder (a) Image shows dorsum of hand with multiple small pinhead sized, round, skin-coloured, waxy papules located symmetrically on the dorsum of the hands

Fig 1(b): Polarised dermoscopy at 10x magnification shows yellowish brown globules with dark brown reticular structures in its centre suggestive of septae along with small linear vessels in some.

Fig 2: A hyperkeratotic epidermis with underlying nodular masses of homogenous eosinophilic material having fissures and clefts in upper dermis. A thin grenz zone of uninvolved collagen can be seen. Clumping of elastotic fibres is seen at the periphery of colloid.

Discussion

Nodular amyloidosis, acral persistent pustular mucinosis, calcinosis cutis, milia cysts, multiple syringoma and amyloidosis can be considered as differential diagnoses if the histopathology is not characteristic and can be ruled out on the basis of special stains, immunohistochemistry (IHC) and electron microscopy (EM) [4].

On special stains, colloid stain was positive on periodic acid–schiff (PAS). On IHC, it stains positive for IgM, IgG and NKH-1 antigen and negative for cytokeratin, type IV collagen, laminin and light chain immunoglobulins in contrast to amyloidosis [5].

Under EM, the colloid ultrastructure presents as an amorphous, granular electron-dense material with short, poorly-defined, branching filaments that are significantly smaller than those observed in amyloidosis [5].

Treatment modalities are limited in these cases. Limiting exposure from harmful UV radiations from the sun is the most preferred protective measure; however, topical retinoids, dermabrasion, diathermy, cryotherapy, and Er-YAG laser are also attempted to cure the condition [1,5].

Conclusion

In our literature review, we did not find any documentation of colloid milium association with Fitzpatrick skin type 4 disorder. Major differentials of colloid include amyloid, calcinosis and mucinosis. A thorough clinical and histopathological review is required for a specific diagnosis.

Declarations

Source(s) of support: Nil

Presentation at a meeting: Nil

Conflicting Interest (If present, give more details): None

Acknowledgement if any: None

Informed consent statement

The author(s) confirm that informed consent has been obtained from the involved patient and, they have given approval for their photograph without revealing the identity to be published in this case letter.

References

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