Answer of Dermatopathology Case 89

Digital Mucous Cyst

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Abstracts:

Digital mucous cysts. J Cutan Med Surg. 2010 Sep-Oct;14(5):199-206
BACKGROUND: Digital mucous cyst (DMC) is a common benign condition, but consensus has not been reached regarding its pathogenesis and treatment.
OBJECTIVE: This review provides a concise overview of DMCs.
METHODS: The review presents the literature pertaining to the etiology, pathogenesis, classification, clinical features, epidemiology, differential diagnoses, diagnosis, and management of DMCs.
RESULTS: DMCs have a predilection for middle-aged patients, a good prognosis, and a high recurrence rate. DMCs may occur in one of three locations on the distal digit. They arise owing to a metaplastic or degenerative process. Preexisting osteoarthritis is common and may be an etiologic factor in patients with DMCs. A number of conservative and surgical treatments are available depending on the structures and locations involved.
CONCLUSION: Studies with greater sample size and longer follow-up would enrich current knowledge of the benefits, recurrences, and complications for each treatment modality.

A case of herpetiform appearance of digital mucous cysts. Ann Dermatol. 2010 May;22(2):194-5. Epub 2010 May 18.
A digital mucous cyst (DMC) is clinically characterized by a round to oval, translucent, smooth nodule localized to the dorsal aspect of the distal digits near the distal interphalangeal joint. It usually presents as a solitary lesion, and multiple lesions are uncommon. An 88-year-old man presented with herpetiform translucent papules on the right thumb. We first diagnosed the lesion as molluscum contagiosum or herpetic whitlow. Histopathology showed a cystic space containing mucinous material and numerous fibroblasts surrounded by mucinous stroma in the upper dermis. The lining of the cyst wall was not apparent and mucinous material was stained with Alcian blue, indicating a diagnosis of DMC.

MR imaging of digital mucoid cysts. Radiology. 1996 Aug;200(2):531-6.
PURPOSE: To assess the usefulness of magnetic resonance (MR) imaging in the diagnosis and clarification of the physiopathology of digital mucoid cysts.
MATERIALS AND METHODS: Twenty-three patients (14 women, nine men; aged 52-75 years) with mucoid cysts underwent MR imaging at 1.5 T with a local surface gradient coil. The pixel size was 117 microns in one direction. T2 relaxation times were measured. Contrast material was intravenously administered in 15 patients.
RESULTS: All mucoid cysts had high signal intensity and sharp borders on T2-weighted images. Intracystic septa were present in nine patients (39%). Most cysts were solitary (n = 13) and/or in the proximal nail fold (n = 16). Satellite cysts were present in five patients. Nineteen patients (83%) had cysts with pedicles that extended to the joint. Osteoarthritis of the distal interphalangeal joint was present in 16 patients (70%). Five patients (22%) had multiple flattened cysts that were usually independent of the joint. In seven patients (30%), MR images showed cysts beneath the nail plate.
CONCLUSION: Digital mucoid cysts may be polymorphic. MR imaging is helpful when cysts are in the nail bed.

Cutaneous mucinosis. Ann Dermatol Venereol. 1993;120(1):75-87.
The cutaneous mucinoses are a heterogeneous group of diseases in which mucin accumulates in the skin or within the hair follicle. We divide the cutaneous mucinoses into two groups: the distinctive cutaneous mucinoses in which the mucin deposit is a distinctive histopathologic feature that manifests as a clinically specific lesion, and the diseases associated with histopathologic mucin deposition as an additional finding. This article deals with the clinical and histopathologic features and the treatment of the distinctive cutaneous mucinoses and updates their classification. They may be divided, according to the microscopic location of mucin, into dermal and follicular mucinoses. The former group includes; lichen myxedematosus, acral persistent papular mucinosis, reticular erythematous mucinosis, scleredema, dysthyroidotic mucinoses (i.e. localized myxedema, generalized myxedema, papular mucinoses associated with thyroid diseases), papular and nodular mucinosis associated with lupus erythematosus, self-healing juvenile cutaneous mucinosis, cutaneous mucinosis of the infancy, cutaneous toxic mucinoses (papular mucinosis of the toxic oil syndrome and of eosinophiliamyalgia syndrome), neuropathia mucinosa cutanea, cutaneous focal mucinosis, mucous cyst (digital and of the oral mucosa), while the latter group includes Pinkus' follicular mucinosis and urticaria-like follicular mucinosis.