Follicular mucinosis

ARTICLE

A 15-year-old boy presented with an asymptomatic lesion on the shoulder that had been present for almost a year. Cutaneous examination revealed numerous small, coarse, follicular papules which were grouped in one plaque of 5 cm diameter. A diminish amount of vellus hair was seen on the lesion (Fig. 1). Histological examination of the lesion showed disruption with formation of cystic spaces within the epithelial cells of the pilosebaceous unit (Fig. 2). Physical examination, routine blood analysis, chest X-ray and abdominal ultrasound examination were all within normal limits. The patient was treated with intralesional injections of triamcinolone acetonide, the lesion resolved within two months.

Follicular mucinosis

Follicular mucinosis, also known as alopecia mucinosa, was first described by Pinkus [1] in 1957. Follicular mucinosis may have various clinical presentations; hypopigmented, erythematous, eczematous plaque, flesh-colored follicular papules and even as a solitary nodule [2].

The lesion is characterized by diminished vellus hair. In many cases anesthesia to cold or touch may be present. The lesions are distributed mostly on the face, neck and scalp but may appear on any part of the body [2].

Two main forms of follicular mucinosis are known: a benign, idiopathic condition found mostly in children and adolescents, characterized by the presence of one or a few lesions located on the head, neck and upper arm. The lesions resolved spontaneously within several months to two years [2-5]. The second form is found among older patients and is associated with systemic diseases including lymphoma, particularly mycosis fungoides, but also lupus erythematosus and sarcoidosis [2-9].

The diagnosis of follicular mucinosis is based mainly on histological findings. Follicular mucinosis is characterized by vacuolization, cystic degeneration and deposition of mucin in the pilosebaceous unit. The mucin consists of acid mucopolysaccharides (hyaluronic acid and/or sulfates) that stain metachromatically with toluidine blue, Giemsa and alcian blue stains. The affected follicles lose the ability to produce normal keratin therefore hair production is diminished [2, 10].

In children, the disease may resolved spontaneously or after topical application or intralesional injection of corticosteroids. Since no single clinical or histopathological observation predicts which patients with follicular mucinosis will have a benign course. Patients should be followed to rule out any possible underlying disease [2-10].

REFERENCES

1. Pinkus H. Alopecia mucinosa. Arch Dermatol 1957; 76: 419-24.

2. Follicular mucinosis. In: Arnold HL, Odom RB, James WD, eds. Andrew's diseases of the skin. 8th ed. WB Saunders company, 1990: 190-1.

3. Raab B, Soltani K, Medenica M. Follicular mucinosis in childhood. Cutis 1982; 30: 87-90.

4. Strumia R. Ringworm of the chin. Alopecia mucinosa. Arch Dermatol 1989; 125: 287-92.

5. Schwartz BK, Demos PT, Baughman RD, et al. Indurated facial plaques in young man. Follicular mucinosis. Arch Dermatol 1987; 123: 937-42.

6. Binnick AN, Wax FD, Clendenning WE. Alopecia mucinosa associated with mycosis fungoides. Arch Dermatol 1978; 114: 791-2.

7. Nickoloff BJ, Wood C. Benign idiopathic versus mycosis fungoides-associated follicular mucinosis. Pediatr Dermatol 1985; 2: 201-6.

8. Kanno S, Niizuma K, Machida S, et al. Follicular mucinosis developing into cutaneous lymphoma: report of two cases and review of the literature and 64 cases in Japan. Arch Dermatol Venereol 1984; 64: 86-8.

9. Wilkinson JD, Black MM, Chu A. Follicular mucinosis associated with mycosis fungoides presenting with gross cystic changes on the face. Clin Exp Dermatol 1982; 7: 333-9.

10. Gibson LE, Muller SA, Lieferman KM, et al. Follicular mucinosis: clinical and histopathologic study. J Am Acad Dermatol 1989; 20: 441-6.