History
The clinical features of follicular infundibulum tumor depend on the subtype, which may be either solitary or eruptive. In the eruptive form, multiple lesions develop over time. Neither subtype usually causes symptoms.
Physical Examination
Solitary follicular infundibulum tumors have no distinctive clinical features. Usually, a solitary tumor presents as a scaly nodule up to 1.5 cm in diameter and located on the head or neck. A solitary tumor frequently is misdiagnosed as basal cell carcinoma or seborrheic keratosis.
Eruptive follicular infundibulum tumor lesions have been described in most reports as a sudden onset of multiple (up to 200), variably scaling, hypopigmented macules and papules confined to the head, neck, and upper trunk. [7] They resemble tinea versicolor, pityriasis alba, or disseminated superficial actinic porokeratosis. Vitiligolike hypopigmented facial macules have also been reported. [8] The terms infundibulomas and infundibulomatosis apply to the eruptive form.
An article from 2004 described a case of multiple infundibulomas manifesting as hundreds of 4- to 10-mm red-brown papules in the intertriginous areas, resembling Darier disease. [9] A 2009 article described ill-defined, scaly, reticulated plaques on photodamaged skin resembling eczema craquel é, located on the bilateral sides of the face and neck. These plaques were of 5 years' duration and were accentuated with sun exposure. Biopsy showed multiple infundibulomas. [10]
Rare cases have been associated with nevus sebaceous and Cowden syndrome. [11]
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Tumor of the follicular infundibulum shows a platelike dermal tumor with anastomosing islands and cords with connections to the overlying epidermis and horn cysts (hematoxylin and eosin stain, 40X magnification).
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Tumor of the follicular infundibulum shows epidermal connections, horn cysts, and anastomosing islands (hematoxylin and eosin stain, 100X magnification).
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Tumor of the follicular infundibulum shows epidermal connections, peripheral palisading, and horn cyst (hematoxylin and eosin stain, 400X magnification).
