Birt-Hogg-Dube Syndrome (BHDS) Workup

Updated: Aug 23, 2019
  • Author: Krista K Buckley, DO; Chief Editor: Dirk M Elston, MD  more...
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Workup

Imaging Studies

Conduct renal ultrasonography, MRI or CT; CT scanning of the abdomen and pelvis; chest radiography.

Birt-Hogg-Dubé syndrome (BHDS) has been reported in association with various types of renal tumors, such as oncocytoma and a variant of papillary renal cell carcinoma. [66] Birt-Hogg-Dubé syndrome is autosomal dominant; therefore, screen patients and their relatives for renal cancer. Because renal neoplasms often are asymptomatic during the growth phase, an earlier onset of fibrofolliculomas and trichodiscomas may serve as a marker.

Screening chest radiography should be advised for patients and family members because of the Birt-Hogg-Dubé syndrome association with recurrent spontaneous pneumothorax, bullous emphysema, and lung cysts. A significant association is apparent between the number and location of lung cysts and pneumothorax. [25]

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Other Tests

Consider colonoscopy. Colonic polyps and colonic adenocarcinoma have been previously reported as associated findings of Birt-Hogg-Dubé syndrome; however, one study in a large cohort of patients with Birt-Hogg-Dubé syndrome did not confirm a colorectal cancer association. [26]

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Procedures

Skin biopsy is necessary to confirm trichodiscomas, fibrofolliculomas, and perifollicular fibromas.

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Histologic Findings

Fibrofolliculoma consists of a well-formed hair follicle with a dilated infundibulum containing laminated keratin. Radiating from the epithelium of the hair follicle are anastomosing epithelial strands of 2- to 4-mm thickness within a well-circumscribed mantle of loose mucinous connective tissue. These strands may arise from sebaceous epithelium deeply situated in the epidermis. [67] The entire tumor is embedded in a fibrous or fibromucinous orb.

In its classic description, trichodiscoma represents a small hamartomatous tumor of the hair disk (Haarscheibe). Pinkus et al described a constant topographic relationship of the hair follicle to the periphery of the papule. Other prominent features of trichodiscomas include a proliferation only of the fibrovascular component of the hair disk, small melanin-granule–containing cells in the substance of the tumor, and occasional myelinated nerves at the base of the lesion. Studies suggest that trichodiscomas also may be closely related to fibrofolliculomas, and their histologic appearance may relate to the plane of sectioning. [68, 69]  The term mantleoma has been used to describe the continuum of appearance between the two tumors. [70]

Acrochordons usually demonstrate papillomatosis, hyperkeratosis, and regular acanthosis. In Birt-Hogg-Dubé syndrome, papules identified clinically as acrochordons are not evaluated histologically as a routine; however, reports of clinically appearing acrochordons associated with Birt-Hogg-Dubé syndrome were evaluated and showed histologic findings consistent with fibrofolliculomas. Histologic study of 12 biopsy specimens of acrochordonlike lesions revealed infundibular structures within a core of fibrovascular mesenchyme, with epithelial strands extending from the basal layer. Future studies may confirm these findings.

Perifollicular fibroma classically is characterized by an unaltered hair follicle, commonly containing a hair shaft and surrounded by a distinct, circumferentially arranged, collagen fibrous sheath. Histologic study of perifollicular fibromas has revealed that sectioning techniques may skew interpretation of the lesions. Lesions described as perifollicular fibroma on horizontal sections were reexamined in vertical cuts and demonstrated histologic features similar to fibrofolliculoma, such as mantlelike strands of epithelium and sebaceous lobules at deeper levels of the epidermis. Thus, the entity of perifollicular fibroma may represent a transverse cut of a fibrofolliculoma, rather than a perifollicular fibroma. [8, 61, 65]

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