Skin nontumor
Dermal collagen and elastic tissue alterations and metabolic disorders
Colloid milium
Board of reviewers: Sepideh Nikki Asadbeigi, M.D.
Last author update: 5 December 2024
Last staff update: 5 December 2024
Copyright: 2024, PathologyOutlines.com, Inc.
PubMed Search: Colloid milium
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Case reports | Treatment | Clinical images | Frozen section description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Videos | Sample pathology report | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Holland TE, Logemann NF. Colloid milium. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skinnontumorcolloidmilium.html. Accessed December 21st, 2024.
Definition / general
- Colloid milium is a benign eruption of papules that represents deposition of colloid from elastic fiber degradation, most commonly from chronic sun exposure (or in the case of the juvenile form of the disease, degeneration of ultraviolet [UV] transformed keratinocytes)
- Several subtypes have been described, including classic adult colloid milium, juvenile, pigmented and colloid degeneration
Essential features
- Colloid milium is a benign depositional disorder in the superficial dermis and is most likely composed of degenerated dermal elastic fibers
- Histologically, there are amorphous eosinophilic nodular deposits in the papillary dermis with fissures that give it a cracked appearance
- Treatment is not necessary but commonly used modalities include lasers, chemical peels and dermabrasion (J Eur Acad Dermatol Venereol 2016;30:490)
Terminology
- Colloid degeneration of the skin
- Elastosis colloidalis conglomerata
- Miliary colloidoma
- Papular elastosis
ICD coding
Epidemiology
- Adult form
- Middle aged to elderly
- Fair skinned (Fitzpatrick types I & II) (Adv Biomed Res 2013;2:28)
- M:F = 4:1 (Bolognia: Dermatology, 5th Edition, 2024)
- Juvenile form
- Develops before puberty (Dermatol Pract Concept 2024;14:e2024197)
- Possible autosomal dominant or autosomal recessive inheritance (J Am Acad Dermatol 2002;46:S5)
- Pigmented form
- Associated with exogenous use of hydroquinone
Sites
- Usually involves chronically sun exposed skin of the head and neck, particularly the face, posterior neck and dorsal hands
Pathophysiology
- Largely unknown (see Etiology)
Etiology
- Adult form: unknown but thought to be a result of chronic ultraviolet damage to elastic fibers within the dermis (J Cutan Pathol 1985;12:147)
- Juvenile form: ultraviolet light induced damage to epidermal keratinocytes in genetically susceptible individuals (Maedica (Bucur) 2019;14:173)
- Pigmented form: variant of the adult form, with topical application of hydroquinone or phenols contributing to its pathogenesis (J Dermatol 2020;47:e127)
Clinical features
- Adult and juvenile forms
- Dome shaped and clear, yellow or yellow-brown papules over areas susceptible to frequent sun exposure (Adv Biomed Res 2013;2:28)
- Pigmented forms
- Similar to adult and juvenile forms; gray-brown colored papules (Br J Dermatol 1975;93:613)
Diagnosis
- Diagnosis can be made with biopsy of one of the lesions
Case reports
- 10 year old boy with translucent papules over the nose and central face (Maedica (Bucur) 2019;14:173)
- 35 year old man with symmetric skin lesions over forearms and hands (Indian Dermatol Online J 2023;14:521)
- 53 year old man with pigmented papules on the dorsa of hands, nose and ears (J Dermatol Case Rep 2015;9:42)
- 70 year old man with papules and plaques on the face, hands and forearms (Dermatol Online J 2021;27:3)
Treatment
- Laser therapy (e.g., long pulsed Er:YAG) (Dermatol Surg 2002;28:215)
- Dermabrasion (Dermatol Surg 2002;28:780)
- Intense pulsed light (IPL) (J Pak Med Assoc 2008;58:207)
- Chemical peels
Clinical images
Images hosted on other servers:
Yellowish, translucent, waxy papules with purpura
Tan-yellow, smooth, translucent papules
Pigmented colloid milium: black-bluish papules
Frozen section description
- Staining with crystal violet, Congo red and thioflavin T may be more readily appreciated on frozen section compared with paraffin embedded tissue (Arch Dermatol 1972;105:684)
Microscopic (histologic) description
- Deposits of colloid milium demonstrate eosinophilic, homogeneous colloid material in the superficial papillary dermis, most often with clefts and fissures giving a cracked appearance
- Grenz zone overlying these deposits is commonly present
- Solar elastosis is commonly observed surrounding the nodules in adult form
- Stellate and spindle shaped fibroblasts occupy fissures between fragmented deposits
- Epidermal atrophy
- In the juvenile form, adjacent epidermis with apoptosis
- In the pigmented form, there are collections of pigmented colloid bodies
- Reference: J Am Acad Dermatol 2002;46:S5
Microscopic (histologic) images
Contributed by Antoanella Calame, M.D., Nicholas Logemann, D.O. and Christof Erickson, M.D.
Eosinophilic deposits
Grenz zone
Solar degeneration
Amorphous deposits with clefting
Superficial deposits
Spindled fibroblasts
Fissuring
Spindle and stellate fibroblasts
PAS
Positive stains
- Crystal violet
- Congo red with apple green birefringence
- Thioflavin T
- PAS
- Verhoeff-van Gieson (VVG)
- Dylon (Arch Dermatol 1972;105:684)
- Pinkus acid orcein-Giemsa (Int J Dermatol 2011;50:1531)
Negative stains
- Pagoda red
Electron microscopy description
- Amorphous and granular material with wavy, ill defined, short and branching filaments
- Active fibroblasts
- Juvenile form: fibrillary masses with whirling and rare nuclear remnants (J Cutan Pathol 1983;10:111)
Videos
Dermatopathology review of colloid milium
Sample pathology report
- Skin, left nasal sidewall, shave biopsy:
- Colloid milium (see comment)
- Comment: Sections show eosinophilic collections of amorphous material with clefting and cracking. Colloidal iron fails to highlight these deposits, which supports the diagnosis above.
Differential diagnosis
- Primary cutaneous amyloidosis:
- No Grenz zone
- No laminin or type IV collagen
- Plasma cells common
- Positive staining for some cytokeratins, such as CK5/6 (although this may also be found in the juvenile variant of colloid milium)
- Electron microscopy may be necessary for distinction (Am J Dermatopathol 2009;31:472)
- Lipoid proteinosis:
- No laminin or type IV collagen
- Dermal deposits accentuated around blood vessels
- Erythropoietic protoporphyria:
- Hyaline deposits around superficial blood vessels
- Vacuolization of basilar epidermis
Additional references
Board review style question #1
A 69 year old man presents to the clinic with monomorphic, skin colored to translucent papules distributed over the face and bilateral dorsal forearms. A biopsy of one of the lesions demonstrates the image shown above. Which of the following best describes the eosinophilic inclusion component in this case?
- Calcium pyrophosphate
- Collagen IV
- Dermal elastic fibers
- Immunoglobulin light chains
Board review style answer #1
C. Dermal elastic fibers. The clinical history and histological features are consistent with a diagnosis of colloid milium, which is a dermal depositional disease characterized by ultraviolet induced degeneration of dermal elastic fibers. Answer B is incorrect because collagen IV is a major component of the lamina densa of the cutaneous basement membrane zone. Collagen IV is commonly found deposited in other disorders such as lipoid proteinosis, cutaneous collagenous vasculopathy (around dermal superficial vessels), porphyria cutanea tarda and spiradenomas (around tumor nodules). Answer D is incorrect because this describes the deposits found in primary systemic amyloidosis and primary cutaneous nodular amyloidosis. Answer A is incorrect because calcium pyrophosphate is found in cutaneous deposits of pseudogout.
Comment Here
Reference: Colloid milium
Comment Here
Reference: Colloid milium
Board review style question #2
Which of the following is most likely to be involved in the pathogenesis of colloid milium?
- Endogenous familial hypertriglyceridemia
- Plasma cell dyscrasia
- Storage of excessive glycosaminoglycans within the dermis
- Ultraviolet exposure
Board review style answer #2
D. Ultraviolet exposure. Colloid milium is a disorder that is most likely a result of ultraviolet damage to elastic fibers within the dermis, which results in the formation of nodules of homogeneous colloid material within the papillary dermis. This is evidenced by positive staining with the elastin stain Verhoeff-van Gieson. Answer B is incorrect because plasma cell dyscrasias may be associated with gammopathies, which have associations with multiple other dermatologic disorders such as necrobiotic xanthogranuloma (from immunoglobulin G kappa monoclonal gammopathy), Sweet syndrome (immunoglobulin A) and Schnitzler syndrome (immunoglobulin M). Answer A is incorrect because endogenous familial hypertriglyceridemia results in increased very low density lipoproteins and hypertriglyceridemia, which results in eruptive xanthomas. Answer C is incorrect because storage of excessive glycosaminoglycans within the dermis is involved in mucopolysaccharidoses.
Comment Here
Reference: Colloid milium
Comment Here
Reference: Colloid milium
