A patient, aged 65 years, presented with complaints of a bump on her toe that had developed three months prior.
On physical exam, there was a translucent papule over the distal interphalangeal joint of the second left toe. The papule was pierced with an 18 gauge needle and a clear jelly-like material was easily expressed.
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Also known as myxoid cysts, digital mucous cysts are cysts that usually appear on the distal portion of the fingers and occasionally the toes. The lesions present as a singular skin-colored to blue cyst with clear to white thick fluid inside.
If the cyst is overlying the nail matrix, it may disrupt and cause depressions and groves due to the cyst disrupting the nail matrix. Digital mucous cysts are more commonly seen in women.
Patients with multiple digital mucous cysts may have one of the many connective tissue diseases. This can be seen in juvenile rheumatoid arthritis and systemic scleroderma.
It has also been seen in patients with osteoarthritis where the cyst develops on the digit with an affected joint. Indeed, on surgical removal of a cyst, a tract to the joint space may be seen. Finally, it has been reported to appear in patients whose work involves repeated trauma to the area.
Histologically, these cysts are not contained in a layer of epithelium. Instead, they have a fibrous wall. Treatment options include steroid injections, repeat drainage of the cyst, and surgical excision of the cyst. A novel technique involving identifying and destroying the tract from the cyst to the joint space has a very high cure rate.
Also known as a trichilemmal cysts or isthmus-catagen cysts, pilar cysts are cysts that form around a hair follicle and are most often found on the scalp. They appear similar to an epidermoid cyst, and are clinically firm and mobile. They are distinguished by their lining, which is a stratified squamous epithelium thought to be derived from the hair follicle’s root sheath.
Treatment is either surgical excision or by using a punch biopsy to open the cysts and removing the contents, including the lining.
Epidermal inclusion cyst
Also called epidermoid cysts, epidermal cysts, or infundibular cysts, epidermal inclusion cysts are the most commonly seen cysts, clinically. They can occur anywhere, with a tendency to appear on the face and trunk. They can range in size from a few millimeters (where they can be referred to as milia) to many centimeters. Clinically, they appear as a nodule which is moveable relative to the underlying structures but is attached to the overlying skin.
They are distinguished by their lining, which is a stratified squamous epithelium. Treatment is similar to that of pilar cysts.
Also called cysts of Moll or sudoriferous cysts, apocrine hidrocystomas are solitary, translucent, skin to blue colored lesions that appear almost exclusively on the face and most commonly the eyelids.
Jason Preissig, MD, is a graduate of Baylor College of Medicine
Adam Rees, MD, a graduate of the David Geffen School of Medicine at UCLA, practices dermatology in Los Angeles.
- William J, Berger T, Elston D. 2011. “Chapter 9 – Mucinoses.” Andrews’ Diseases of the Skin: Clinical Dermatology. Philadelphia: Saunder Elsevier. Print.
- William J, Berger T, Elston D. 2011. “Chapter 29 – Epidermal Nevi, Neoplasms, and Cysts.” Andrews’ Diseases of the Skin: Clinical Dermatology. Philadelphia: Saunder Elsevier. Print.
- Bolognia J, Jorizzo J, Rapini R. 2008. “Section 18 – Neoplasms of the Skin” Dermatology. St. Louis, MO: Mosby/Elsevier. Print