You are in: eMedicine Specialties > Dermatology > BENIGN NEOPLASMS Follicular Infundibulum TumorArticle Last Updated: Dec 15, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Brad S Graham, MD, Consulting Staff, Dermatology Associates of Tyler, East Texas Medical Center; Trinity Mother Francis Hospital Brad S Graham is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, and American Society of Dermatopathology Editors: Terry L Barrett, MD, Director, Associate Professor, Department of Dermatology, Division of Dermatopathology and Oral Pathology, Johns Hopkins University School of Medicine; David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Director, Division of Dermatology, Scott and White Clinic; Director Dermatology Residency Training Program, Scott and White Clinic; Edward F Chan, MD, Clinical Assistant Professor, Department of Dermatology, University of Pennsylvania School of Medicine; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; William D James, MD, Paul R Gross Professor of Dermatology, University of Pennsylvania School of Medicine; Vice-Chair, Program Director, Department of Dermatology, University of Pennsylvania Health System Author and Editor Disclosure Synonyms and related keywords: tumor of the follicular infundibulum, infundibulomas, infundibulomatosis INTRODUCTIONSection 2 of 9
  BackgroundTumor of the follicular infundibulum is a rare benign adnexal tumor arising from the follicular infundibulum. The histopathology of the tumor is distinctive, which occurs as a platelike dermal nodule with multiple thin connections to the overlying epidermis (see Media Files 1-3). The tumor usually manifests as a single lesion, but an eruptive (multiple) form may occur. PathophysiologyA benign tumoral proliferation that arises from the follicular infundibulum. The external root sheath of the follicle has been shown to give rise to these tumors. A possible relation to sun exposure has been reported. FrequencyInternationalFollicular infundibulum tumor is uncommon. Since the original report from Mehregan and Butler in 1961, only a few new cases have been reported. The overall relative frequency ranges from 3-10 cases per 100,000 specimens examined. Mortality/MorbidityThe tumor is benign, although malignant transformation to a basal cell carcinoma was reported twice in a patient with multiple lesions. RaceNo racial predilection is known. SexA slight female predominance is recognized. AgeMost cases occur in patients older than 60 years. CLINICALSection 3 of 9
HistoryThe 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. PhysicalSolitary 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 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. They resemble tinea versicolor, pityriasis alba or disseminated superficial actinic porokeratosis. 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. Rare cases have been associated with nevus sebaceous and Cowden syndrome. CausesThe cause of follicular infundibulum tumor is unknown. DIFFERENTIALSSection 4 of 9
Basal Cell Carcinoma Pityriasis Alba Porokeratosis Seborrheic Keratosis Tinea Versicolor WORKUPSection 5 of 9
Histologic FindingsTumor of the follicular infundibulum is a histologic diagnosis. Most cases typically resemble the original description by Mehregan and Butler. A platelike fenestrated subepidermal tumor extends horizontally under the epidermis with multiple cordlike connections to the overlying epidermis. Upon serial sectioning, connections between the pale-staining, glycogen-containing, tumoral keratinocytes and the external root sheath of adjacent hair follicles usually can be found. Peripheral palisading of the basal cells is present. Peripheral palisading of basaloid cells frequently is observed. Pale staining results from the presence of glycogen analogous to the external root sheath and is confirmed by periodic acid-Schiff (PAS) stain with diastase digestion. A dense band or brushlike network of elastic fibers frequently is demonstrated at the border of the tumor, again analogous to the normal hair follicle. This can be observed readily using Verhoeff, van Gieson, or orcein stains. A case report from 2001 noted foci of sebaceous differentiation within the fenestrated epithelium. TREATMENTSection 6 of 9
Medical CareFor multiple and eruptive tumors, treatment usually is unrewarding, since attempted treatment using corticosteroids, keratolytics, cryotherapy, and topical and systemic retinoids results in only partial improvement. Surgical CareFor solitary tumors, treatment is simple excision. FOLLOW-UPSection 7 of 9
Prognosis
MULTIMEDIASection 8 of 9
REFERENCESSection 9 of 9
Follicular Infundibulum Tumor excerpt Article Last Updated: Dec 15, 2006 | ||||||||||||||||||||||||||||
