Chapter 35 - Sebaceous Hyperplasia And Neoplasms
(The chapter is a Demonstration of the features available in the Full Version of the Atlas)
SEBACEOUS HYPERPLASIA
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Solitary or multiple 1 to 3 mm in diameter, yellowish, umbilicated papules typically on the forehead (Fig. 35-1) or cheeks of adults past middle age. Sometimes it can be seen in younger individuals.
MICROSCOPIC FEATURES:
Hyperplastic mature sebaceous gland with multiple enlarged lobules centrally located about an ectatic infundibulum or steatic duct (Fig. 35-2,35-3)
Lobules have one or two layers of a germinative epithelium composed of basaloid or cuboidal cells without lipid droplets (Fig. 35-4).
Lobules show multiple layers of mature sebocytes with abundant lipid and scalloped nuclei (Fig. 35-5).
DIFFERENTIAL DIAGNOSIS:
In nevus sebaceus the sebaceous lobules are aberrant, with the ectatic steatic duct opening directly into the epidermis.
Nevus sebaceus shows epidermal hyperplasia and, occasionally, apocrine glands.
In rhinophyma the sebaceous glands are hyperplastic over a larger area, and mild dermal fibrosis and perifollicular granulomatous infiltrate are observed.
REFERENCES:
Bhawan J, Calhoun J. Premature sebaceous gland hyperplasia. J Am Acad Dermatol 1983;8:136.
DeVillez RL, Roberts LC. Premature sebaceous gland hyperplasia. J Am Acad Dermatol 1982;6:933-5.
NEVUS SEBACEUS
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Nevus sebaceus of Jadassohn presents as a congenital, linear, oval or geographic plaque on the scalp or face (Fig. 35-6,35-7). At puberty, the plaque becomes verrucous or nodular (Fig. 35-8). In adults, basal cell carcinoma and syringocystadenoma papilliferum may arise in association with nevus sebaceus.
MICROSCOPIC FEATURES:
In childhood, there is mild irregular epidermal hyperplasia and abrupt absence of mature hair follicles (Fig. 35-9, 35-10).
Immature or vestigial hair structures with basaloid budding are identified adjacent to superficial immature sebaceous glands (Fig. 35-11,35-12,35-13,35-14).
Ectopic apocrine glands are seen in a subset of the cases (Fig. 35-15,35-16) which are distributed in a vertical pattern in place of absent mature hair follicles (Fig. 35-9,35-10,35-11).
In the first few months following birth and at puberty, numerous irregular sebaceous glands are seen.
The immature sebaceous glands are superficially located and often show an ectatic steatic duct or sebaceous gland opening directly into the surface epithelium.
Nevus sebaceus may have few sebaceous elements and show predominantly verrucous epidermal hyperplasia (Fig. 35-17) mimicking seborrheic keratosis; however, occasional immature sebaceous glands may be identified (Fig. 35-18).
Immature or atypical basaloid hyperplasia may be seen at the base of adjoining rete ridges (Fig. 35-19, 35-20) and may be confused with basal cell carcinoma.
Basal cell carcinoma may arise in association with the immature basaloid buds (Fig. 35-21,35-22).
Syringocystadenoma papilliferum is also commonly observed associated with nevus sebaceus in adults.
DIFFERENTIAL DIAGNOSIS:
Epidermal nevus exhibits epidermal hyperplasia similar in appearance to nevus sebaceus but usually does not show aberrant immature pilosebaceous architecture; however, some lesions have overlapping features of both entities and have been called organoid nevi.
Sebaceous hyperplasia shows increased mature sebaceous gland lobules that are surrounding a normally positioned central steatic duct extending to the base of the infundibulum, and the hyperplastic lobules slightly displace upward the normal epidermis.
Seborrheic keratosis may be difficult to differentiate from some nevus sebaceus lesions especially on shave biopsy.
REFERENCES:
Alessi E, Wong SN, Advani HH, et al. Nevus sebaceus is associated with unusual neoplasms. An atlas. Am J Dermatopathol 1988;10:116-27.
Brownstein MH, Shapiro L. The pilosebaceous tumors. Int J Dermatol 1977;16:340-52.
Domingo J, Helwig EB. Malignant neoplasms associated with nevus sebaceus of Jadassohn. J Am Acad Dermatol 1979;1:545-56.
Jang IG, Choi JM, Park KW, et al. Nevus sebaceous syndrome. Int J Dermatol 1999;38:531-3.
Jones EW, Heyl T. Naevus sebaceus. A report of 140 cases with special regard to the development of secondary malignant tumours. Br J Dermatol 1970;82:99-117.
Mehregan AH, Pinkus H. Life history of organoid nevi. Arch Dermatol 1965;91:574-88.
FOLLICULOSEBACEOUS CYSTIC HAMARTOMA
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The majority of these rare, dome-shaped or polypoid lesions present on the face or scalp; two cases have been reported on the ear and upper back. They are typically around one centimeter in diameter although they may reach a few centimeters in size and one reached several centimeters in size (giant folliculosebaceous cystic hamartoma). They typically arise in adulthood but the giant variant appears to be congenital and enlarges during puberty. It shows numerous-well spaced pores on the surface (Fig. 35-23).
MICROSCOPIC FEATURES:
Multiple folliculosebaceous cystic structures embedded in the dermal stroma
Cystic structures lined by squamous epithelium similar to the infundibular epithelium (Fig. 35-24,35-25, 35-26)
Numerous sebaceous lobules radiate from the central cystic structures (Fig. 35-24,35-25,35-26).
Moderate perifollicular lymphocytic infiltrate may be present (Fig. 35-26).
Dense fibrous stroma and adipose tissue are seen adjacent to sebaceous follicles (Fig. 35-27) as well as a marked increase in reticular dermal collagen bundles and adipose tissue between sebaceous follicles (Fig. 35-28,35-29).
Apocrine glands and rudimentary or mature hair structures may be seen.
DIFFERENTIAL DIAGNOSIS:
Nevus sebaceus of Jadassohn exhibits small aberrant sebaceous glands, budding in close association with a hyperplastic papillomatous epidermis.
Connective tissue nevus shows increased reticular dermal collagen with or without aberrant distribution of adipose tissue; however, the sebaceous glands do not show associated cystic structures.
REFERENCES:
Donati P, Balus L. Folliculosebaceous cystic hamartoma. Reported case with a neural component. Am J Dermatopathol 1993;15:277-9.
Kimura T, Miyazawa H, Aoyagi T, et al. Folliculosebaceous cystic hamartoma. A distinctive malformation of the skin. Am J Dermatopathol 1991;13:213-20.
Yamamoto O, Suenaga Y, Bhawan J. Giant folliculosebaceous cystic hamartoma. J Cutan Pathol 1994;21:170-2.
SEBACEOUS ADENOMA
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Sebaceous adenoma typically presents as a solitary yellow nodule on the face or scalp. It may be solitary or when numerous be associated with the Muir-Torre syndrome (Fig. 35-30). Patients with the Muir-Torre syndrome develop multiple cutaneous sebaceous neoplasms and occasionally keratoacanthomas, as well as multiple adenocarcinomas of the colon, stomach, duodenum, genitourinary tract and larynx, in decreasing order of frequency. The most significant feature of the Muir-Torre syndrome is the excellent prognosis of each of these carcinomas.
Sebaceomas (sebaceous epithelioma) are also associated with the Muir-Torre syndrome. The expression of benign sebaceous neoplasms appears to be most likely a spectrum of disorders, as distinction between sebaceous adenoma and sebaceoma (sebaceous epithelioma) may be difficult. Findings that support a continuum are tumors that appear to be sebaceous adenoma in one lobule or lobules and in another area appear to be sebaceoma (sebaceous epithelioma). A reasonable proposal by some authors is to simply define the use of the term sebaceous adenoma when half or less than 50% of the lesion is composed of germinative and transitional cells, and sebaceoma (sebaceous epithelioma) when greater than 50% of the lesion is composed of germinative and transitional cells. Another reasonable proposal by other authors is to drop the term sebaceous epithelioma and replace it with sebaceoma, as epithelioma is a confusing term that does not clearly signify benignity to some pathologists. Finally, distinction of these benign sebaceous neoplasms is not truly essential; what is important is that they are recognized as sebaceous in origin and that they may be associated with the Muir-Torre syndrome.
MICROSCOPIC FEATURES:
Well-circumscribed, lobulated tumor composed of irregular lobules of several layers of germinative sebocytes and transitional cells which reduces the relative number of mature sebocytes (Fig. 35-31,35-32,35-33)
The germinative cells are somewhat basaloid with uniform round nuclei, and the transitional cells show more eosinophilic cytoplasm (Fig. 35-34).
The ratio of basaloid and transitional cells to sebocytes varies but may be defined as sebaceous adenoma if 50% or more of the cells are sebocytes (Fig. 35-33).
DIFFERENTIAL DIAGNOSIS:
Sebaceous hyperplasia has only one or two cell layers of germinative epithelium, with regular glandular lobules.
Sebaceoma (sebaceous epithelioma) has a majority of the cellular component consisting of germinative cells and transitional cells and scattered central aggregates of mature sebocytes.
REFERENCES:
Banse-Kupin L, Morales A, Barlow M. Torre's syndrome: report of two cases and review of the literature. J Am Acad Dermatol 1984;10:803-17.
Lever WF. Sebaceous adenoma, review of the literature and report of a case. Arch Dermatol Syphild 1948;57:102-11.
Woolhandler HW, Becker WS. Adenoma of sebaceous glands (adenoma sebaceum). Arch Dermatol Syphild 1942;45:734-56.
SEBOACANTHOMA
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Seboacanthoma lesions may present as a solitary or as multiple dome-shaped or verrucous papules, each a few millimeters in diameter. They are typically located on the face. This lesion is considered by some to be a verruca vulgaris with sebaceous differentiation due to overgrowth of normal sebaceous glands. Until there is definitive evidence of human papilloma virus infection in these lesions, the origin of this lesion remains controversial.
MICROSCOPIC FEATURES:
Well-circumscribed verrucous epidermal hyperplasia with (Fig. 35-35) or without hyperkeratosis
Hypergranulosis is often present but may be absent (Fig. 35-36,35-37).
Epidermal acanthosis (Fig. 35-36,35-37)
Basaloid germinative layer may be seen with suprabasilar sebaceous differentiation showing rare or numerous sebocytes (Fig. 35-36,35-37).
DIFFERENTIAL DIAGNOSIS:
Verruca vulgaris usually exhibits coarse keratohyalin granules and occasionally reveals koilocytosis (perinuclear shrinkage artifact with nuclear irregularity).
Nevus sebaceus may show marked epidermal verrucosity with sebaceous differentiation at the base; it is typically a large, broad lesion with aberrant, immature pilosebaceous differentiation and often exhibits deep reticular dermal or subcutaneous ectopic apocrine differentiation.
REFERENCES:
Naylor D. Seboacanthoma. Arch Dermatol 1961;84:642.
SEBACEOMA (SEBACEOUS EPITHELIOMA)
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This tumor presents as a nodule or plaque, typically on the face or scalp. The lesion is associated with the Muir-Torre syndrome as discussed in the section on sebaceous adenoma. Muir-Torre syndrome presents as multiple sebaceous neoplasms, multiple adenomatous polyps and improved survival despite the diagnosis of one or more visceral adenocarcinomas. A discussion on the spectrum of benign sebaceous neoplasms, Muir-Torre syndrome appears in the sebaceous adenoma section.
MICROSCOPIC FEATURES:
Nodular (Fig. 35-38,35-41,35-42) or plate-like dermal (Fig. 35-45) proliferation of basaloid epithelial cells
The tumor is surrounded by an eosinophilic fibrotic stroma (Fig. 35-38,35-41).
The nodules are composed of a majority of basaloid cells and transitional cells with scattered aggregates of mature sebocytes (Fig. 35-39,35-40,35-41,35-42,35-43).
In some cases, sheets of basaloid cells with multiple small vacuoles (immature sebocytes) may be seen (Fig. 35-44).
Mitoses (Fig. 35-43) or central cysts with squamous metaplasia (Fig. 35-41) may be seen.
Intra-epidermal benign sebaceous neoplasms have been described with abundant germinative and transitional cells (Fig. 35-45,35-47) (intra-epidermal sebaceoma or intra-epidermal sebaceous epithelioma).
Transitions to areas with intra-epidermal neoplasms with more abundant sebocytes (intra-epidermal sebaceous adenoma) are seen (Fig. 35-46,35-48).
Basal cell carcinomas with sebaceous differentiation (Fig. 35-49,35-50) are distinguished from benign sebaceous neoplasms by mucinous stroma and separation artifact (Fig. 35-51) or distinct peripheral basal cell nuclear palisading and crowding (Fig. 35-51,35-52).
DIFFERENTIAL DIAGNOSIS:
Sebaceous adenoma will have more regular lobulation, and approximately half of the cells are composed of mature sebaceous cells.
Basal cell carcinoma with sebaceous differentiation or infiltration and replacement of sebaceous lobules; individual cell necrosis, mucinous stroma and separation artifact favor basal cell carcinoma.
REFERENCES:
Dinneen AM, Mehregan DR. Sebaceous epithelioma: a review of twenty-one cases. J Am Acad Dermatol 1996;34:47-50.
Hori M, Egami K, Maejima K, et al. Electron Microscopic study of sebaceous epithelioma. J Dermatol 1978;5:139-47.
Toyoda M, Shoji T, Morohashi M, et al. Benign sebaceous neoplasm with prominent epidermal component. Am J Dermatopathol 1998;20:194-8.
Troy JL, Ackerman AB. Sebaceoma. A distinctive benign neoplasm of adnexal epithelium differentiating toward sebaceous cells. Am J Dermatopathol 1984;6:7-13.
SEBACEOUS CARCINOMA
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The majority of sebaceous carcinoma tumors arise in the elderly on the eyelids and may resemble chronic blepharoconjunctivitis or a chalazion. The tumor is derived from the meibomian glands and rarely from the glands of Zeis. Regional metastases are reported to occur in more than 20% of cases; however, visceral metastases are rare. Sebaceous carcinoma arising at other sites are often associated with the Muir-Torre syndrome, and no cases of sebaceous carcinoma metastasis in these patients have been reported.
MICROSCOPIC FEATURES:
Irregular lobular formation with infiltration of adjacent dermis by an atypical, irregular, undifferentiated epithelium or vacuolated epithelium (Fig. 35-53,35-54,35-55)
The epithelium is composed of spindle to polygonal cells with pleomorphic, hyperchromatic nuclei and pale cytoplasm (Fig. 35-54,35-55).
Vacuolization of cell cytoplasm with occasional scalloping of nuclei by vacuoles (Fig. 35-54,35-55)
Lesions may exhibit pagetoid spread of the malignant cells in the conjunctiva or epidermis.
Intra-epidermal spread may resemble lentiginous or contiguous hyperplasia along the dermo-epidermal junction (Fig. 35-56).
Some tumors show marked atypicality, clear cell change (Fig. 35-57) and extensive invasion.
Oil red 0 or Sudan black fat stains on fresh frozen sections reveal abundant lipid content in sebaceous carcinoma cells.
Immunoperoxidase staining shows tumor cells to be positive for epithelial membrane antigen (EMA) (Fig. 35-58) and negative for GCDFP-15.
DIFFERENTIAL DIAGNOSIS:
Basal cell carcinoma with sebaceous differentiation; sebaceous carcinoma has more pleomorphic nuclei and a more eosinophilic cytoplasm.
Squamous cell carcinoma with invasion and partial replacement of preexisting sebaceous glands; nuclear atypia of the sebocytes is not present.
Pagetoid spread of pale, clear atypical cells in the conjunctiva or epidermis is also seen in extramammary Paget's disease, with positivity for GCDFP-15 on immunoperoxidase staining.
REFERENCES:
Dixon RS, Mikhail GR, Slater HC. Sebaceous carcinoma of the eyelid. J Am Acad Dermatol 1980;3:241-3.
Gloor P, Ansari I, Sinard J. Sebaceous carcinoma presenting as a unilateral papillary conjunctivitis. Am J Ophthalmol 1999;127:458-9.
Graham R, McKee P, McGibbon D, et al. Torre-Muir syndrome. An association with isolated sebaceous carcinoma. Cancer 1985;55:2868-73.
Prioleau PG, Santa Cruz DJ. Sebaceous gland neoplasia. J Cutan Pathol 1984;11:396-414.
Rao NA, Hidayat AA, McLean IW, et al. Sebaceous carcinomas of ocular adnexa: A clinicopathologic study of 104 cases, with five-year follow-up data. Hum Pathol 1982;13:113-22.
Wagner RF, Grande DJ, Bhawan J. Sebaceous carcinoma associated with ocular cicatricial pemphigoid. Skin Cancer 1986;1:41-5.
Wick MR, Goellner JR, Wolfe JT III, et al. Adnexal carcinomas of the skin. II. Extraocular sebaceous carcinomas. Cancer 1985;56:1163-72.
FORDYCE'S SPOTS AND MONTGOMERY'S TUBERCLES
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Fordyce's spots, also known as Fordyce's disease or Fordyce's condition, are yellow pinpoint ectopic sebaceous glands dotting the vermilion border of the lips and the buccal or genital mucosa. Oral lesions increase in frequency with age and appear in the majority of elderly individuals. Montgomery's tubercles are normal sebaceous glands distributed along a circle in the periphery of women's areolae.
MICROSCOPIC FEATURES:
Fordyce's spots are composed of a single sebaceous gland with single or multiple lobules (Fig. 35-59).
No associated hair structures are seen and the steatic duct empties directly to the surface.
Normal cuboidal sebaceous germinative epithelium with basophilic cytoplasm and multiple layers of multivacuolated sebocytes with indented nuclei
Montgomery's tubercles show normal sebaceous glands that do not have an associated hair structure.
Steatic duct with a granular cell layer empties into infundibulum.
Lactiferous ducts are also occasionally seen emptying into the infundibulum.
DIFFERENTIAL DIAGNOSIS:
REFERENCES:
Miles AEW. Sebaceous glands in the lip and cheek mucosa of man. Br Dent J 1958;105:235.
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