Eruptive infundibulomas

Eruptive infundibulomas

Eruptive infundibulomas A distinctive presentation of the tumor of follicular infundibulum Steven Kossard, MB, PhD, FACD, A. G. Finley, MB,BS, F A C D...

4MB Sizes 0 Downloads 54 Views

Eruptive infundibulomas A distinctive presentation of the tumor of follicular infundibulum Steven Kossard, MB, PhD, FACD, A. G. Finley, MB,BS, F A C D , Kenneth Poyzer, MB,BS, FACD, and Emery Kocsard, MD, F A C D

Darlinghurst, New South Wales, Australia Hundreds of asymptomatic pale erythematous lesions, 2 to 15 mm in diameter, with complex angulated shapes in a mantle distribution over the upper portion of the chest and back and the shoulders, developed in two unrelated young men. Actinic porokeratosis, discoid lupus erythematosus, pityriasis versicolor, and acne scars were considered as possible diagnoses, but none of these appeared appropriate. Multiple skin biopsy specimens from both patients showed tumors of follicular infundibulum (infundibulomas), benign platelike proliferations of the external root sheath that were outlined by a prominent brushlike elastic network. This presentation of the tumor of follicular infundibulum can be recognized by its unusual clinical pattern and histopathology. (J AM ACAD DERMATOL1989;21:361-6.)

Tumor of follicular infundibulum is the term given by Mehregan and Butler to2 to a benign hyperplastic lesion that extends from the follicular infundibulum as an epithelial plate connected to the overlying epidermis by pedicles. The majority of lesions have been solitary and not recognized clinically before biopsy, although in two cases ~,3 up to a dozen lesions were present, some of which resembled flat seborrheic keratoses or basal cell carcinomas. In 1983 the case of a patient with hundreds of unusual lesions in a mantle distribution over the upper portion of the chest and back was reported as infundibulomatosis. 4 W e have followed up this case, and recently we have seen a second young man with an almost identical presentation. A description of our findings in both cases may characterize the features that establish eruptive infundibulomas as a recognizable clinicopathologic entity. CASE REPORTS Case 1

A 29-year-old man was initially seen in January 1981 with a 4-year history of numerous asymptomatic lesions From the Skin and Cancer Foundation, St. Vincent's Medical Centre. Reprint requests: Steven Kossard, MB, PhD, FACD, Skin and Cancer Foundation, St. Vineent's Medfcal Centre, 376 Victoria St., Darllnghurst, N.S.W., 2010, Australia.

that were concentrated over the upper portion of the back and chest (Fig. 1) and the shoulders. The individual lesions were irregularly shaped (Fig. 2) and measured 2 to 8 mm in diameter. They were pale and focally erythematous and were bordered by a serrated and broken scale. Some of the lesions coalesced to form unusual patterns wlth an angulated border that had narrow extensions. There were up to five lesions per square centimeter. There was no associated hair loss. During the summer the lesions were more clearly defined inasmuch as they failed to tan. The patient was reexamined 6 years later, and the lesions had persisted without appearing in other sites. Treatment with topical keratolytic agents, including 5% salicylic acid cream and 0.01% retinoic acid gel, proved ineffective. There was no known family history of similar lesions. Case 2 A 23-year-old man was initially seen in 1976 with a history of a severe sunburn some 7 years previously, after which persistent skin lesions appeared over the upper portion of the chest and back and the shoulders. These lesions were hypopigmented and initailly viewed as possibly representing pityriasis versicolor, but no organisms were isolated on skin scraping or culture. The patient returned in July 1980 with an unusual red, scaly eruption; a skin biopsy specimen was obtained to exclude the possibility of actinic porokeratosis, but no specific diagnosis was reached. In August 1987 he again returned and on this occasion had irregular, pale lesions with bizarre shapes and angulated borders. There were hundreds of lesions, 2 to 15 mm in diameter, concentrat361

362

K o s s a r d et al.

Journal of the American Academy of Dermatology

Fig. 1. Numerous irregular lesions over anterior aspect of chest that have failed to tan. Fig. 2. Irregular shapes and indistinct margins of eruptive infundibulomas. Fig. 3. Photomicrograph of an infundibuloma with platelike architecture, pale keratinoeytes, peripheral palisading of nuclei, and prominent elastic network, (Orcein and Giemsa stain; X250,)

Volume 21 Number 2, Part 2 August 1989

Eruptive infundibulomas

363

Fig. 4. Platelike infundibuloma with accentuated elastic network outlining base. (Orcein and Giemsa stain; X60.)

Fig. 5. Peripheral extension with platelike architecture, which is lost in the center of the lesion at the left edge of the photomicrograph. (Orcein and Giemsa stain; xl00.) ed on the upper portion of his trunk and his shoulders. The lesions had a dry, rough surface with an ill-defined border; some were slightly depressed. The surrounding skin showed evidence of chronic solar damage with mottled pigmentation. The patient had a background of asthma and allergic rhinitis, which had not been a problem for some years. There was no known family history of similar skin lesions. The clinical appearance was almost identical to the previous case seen initially in 1981, and a presumptive diagnosis of eruptive infundibulomas was made. HISTOPATHOLOGIC FINDINGS Three separate skin biopsy specimens were taken from each of the two patients. All six specimens

showed an epidermis that was associated with a platelike shelf projecting into the papillary dermis (Figs. 3 and 4), which was connected to the overlying epidermis by pedicles. A striking finding in all biopsies was a dense, brushlike border of elastic fibers that outlined the lesional skin and was situated immediately beneath the dermoepidermal junction (Figs. 3 and 4). Serial sections showed a direct connection of the pale epidermal shelf with the outer root sheath of their follicles in four of the biopsy specimens. Intact acrosyringeal ducts that entered the lesions were occasionally evident. The platelike pattern was prominent at the edges of some lesions (Fig. 5), whereas in the center this

364

Kossard et aL

Journal of the American Academyof Dermatology

Fig. 6. Unusual pattern ofinfundibuloma dernonstratingcentral loss of platelikestructure and epithelial lips accentuating the edges of the tumor surface. (Hematoxylin-eosinstain;

x25.)

pattern was lost and the tumor replaced the whole epidermis (Fig. 6). Furthermore, in some sections the central area was slightly depressed and bordered by epithelial lips composed of well-differentiated keratinocytes (Fig. 7). This border was accentuated by the paler cytoplasm of lesional keratinocytes that contained diastase-digestible glycogen with a positive periodic acid-Schiff reaction. Peripheral palisading of basal keratinocytes was evident, particularly in well-developed lesions with a platelike architecture. Melanin pigment was decreased in the lesion in comparison with the surrounding normal epidermis. The papillary dermis showed edema, variable vascular dilation, scant lymphocytes admixed with mast ceils, and mucin that was positive for Alcian blue at pH 2.5. DISCUSSION The asymptomatic nature, subtle appearance, and variations in the histopathologie findings of eruptive infundibulomas have probably accounted for the delayed recognition of this benign proliferative follicular disorder. The initial diagnosis in our first case was based on the histopathologic studies of three separate skin biopsy specimens that showed changes conforming to the tumor of follicular infundibulum as described by Mehregan and Butler I in i961. In our second patient the clinical pattern and morphology of individual lesions were

eventually recognized as representing eruptive infundibulomas. Both our patients had a striking distribution of hundreds of asymptomatic flat or slightly depressed, hypopigrnented, erythematous lesions, 2 to 15 mm in diameter, over the chest, upper portion of the back, and shoulders. Several clinical diagnoses, including actinic porokeratosis, disseminated discoid lupus erythematosus, pityriasis versicolor, and acne scars, were considered before skin biopsy, but none of these appeared appropriate after careful clinical examination. The lesions of actinic porokeratosis are annular with a distinctive thready border, in contrast to the lesions of eruptive infundibulomas, which have angulated irregular shapes and often an indistinct margin. Centrally the lesions of actinic porokeratosis may be pigmented, with fine keratotic plugs, in contrast to the hypopigmented and erythematous centers with a glazed or rough scale in eruptive infundibulomas. Furthermore, the lesions of actinic porokeratosis almost invariably are present over the limbs, in contrast to the mantle distribution over the upper portion of the trunk as seen in both our patients. Lesions of discoid erythematosus may have indistinct margins and show variable hypopigmentation, erythema, and scaling similar to eruptive infundibulomas. The distribution of discoid lupus

Volume21 Number 2, Part 2 August 1989

Eruptive infundibulomas

365

Fig. 7. Higher-power photomicrograph of the epithelial lip bordering the tumor surface. (Hematoxylin-eosin stain; Xl00.)

erythematosus lesions on the face, hands, arms, and upper portions of the trunk, as well as the associated follicular plugging, pigment incontinence, and scarring seen in lupus erythematosus, should help in differentiating these two disorders. Pityriasis versicolor should provide no problems in clinical differentiation inasmuch as the lesions usually are guttate, and the surface scale is fine, in contrast to the morphology of eruptive infundibulomas. Acne scars also can be readily distinguished in that these are dermal papules, which may be pale but lack the epithelial changes seen in eruptive infundibulomas. The histopathology of actinic porokeratosis, discoid lupus erythematosus, pityriasis versicolor, and acne scars includes features that are clearly established and readily recognized. Because of the rarity of the tumor of follicular infundibulum and the variation that we have seen in its histopathology, the possibility of this diagnosis may not be considered by pathologists in the setting of the previous clinical differential diagnoses. The histopathology of the tumor of follicular infundibulum is characterized by a platelike growth connected by pedicles to the overlying epidermis. Mehregan and Butler ~ found that by serial sections and reconstruction of the lesions a connection with the follicular external sheath could be demonstrated. The individual keratinocytes in the tumor have a pale appearance, which is most apparent at the interface between the tumor and

the normal epidermis. We have found that the junction may have an overhanging lip of normal epithelium, with a preserved granular layer, and that the interface tends to have a sloping edge, with the epithelial plate extending laterally under the normal epidermis. Centrally the platelike pathologic finding may not be present inasmuch as the overlying epidermis may be replaced by the tumor, creating difficulties in diagnosis. Mehregan 2 has emphasized the brushlike elastic network that outlines the epithelial plate of the tumor of follicular infundibulum; we found this feature a useful marker because it was present in all six biopsy specimens in our study. The dense elastic network also helped distinguish portions of the tumor that lacked a platelike structure. Moreover, a platelike epithelial architecture may be seen in association with seborrheic keratoses and basal cell carcinomas, but we have found that these lesions lack the dense elastic brushwork of the follicular infundibuloma. Although sweat ducts were evident in some sections, they probably represent the intact acrosyringium traversing the tumor rather than indicate a lesion with eccrine differentiation. The darker cells of the acmsyringeal duct contrasted with the paler glycogen-rich tumor cells that merged with the external root sheath of the hair follicle infundibulum. The peripheral palisading of basal cells and the distinct elastic network are also features favoring a pilar lesion.

366

Journal of the American Academy of Dermatology

Kossard et al.

We have adopted the term infundibuloma for the tumor of follicular infundibulum. The histopathology of an infundibuloma can readily be distinguished from other benign proliferations of the external root sheath, s including trichilemmomas, inverted follicular keratoses, and pilar sheath acanthomas, all of which involve the follicular infundibulum. Whereas solitary lesions most frequently are encountered in all these entities, multiple trichilemmomas have been recognized as a hallmark of the multiple h a m a r t o m a or Cowden's syndrome? Although our two cases had no recognized associated disorder, further long-term followup is required before this can be excluded. Recently the case of a patient with widespread tumors of follicular infundibulum involving the limbs, trunk, and vulva was published. 7 The papular lesions had been present for 7 years in a 38-year-old woman, and some of them resembled nodular prurigo. There was a photosensitive element, and many of the lesions were pruritic. Two of the lesions underwent degeneration to basal cell carcinoma. In contrast, our two patients had lesions in a more restricted distribution, which were asymptomatic and which have remained relatively stable over a period of at least 10 years without emergence of basal cell carcinomas. Both our cases, however, showed evidence of chronic solar damage with mottled pigmentation. Our more recent patient stated that the lesions had emerged after a sunburn, which raised the possible role of sun exposure in the expression of eruptive infundibulomas.

Topical treatment of our first patient with 5% salicylic acid cream and 0.01% retinoic gel proved ineffective. Etretinate therapy, at a dose of 0.5 mg to 1 m g / k g for a year, resulted in some decrease in the size of lesions in the case from France, 7 which may be a potential therapy in further symptomatic cases.

The almost identical presentation of eruptive infundibulomas in our two patients and the distinctive features we have outlined may serve to identify other persons with this rare disorder. The presence of numerous lesions in this unique variant provides the best means of studying this unusual tumor inasmuch as it is rarely recognized clinically in its solitary form. The relationship to sunlight, the potential to degenerate into basal cell carcinomas, and any systemic associations will be determined only by careful follow-up studies. REFERENCES

1. MehreganAH, Butler JD. A tumor of follicularinfundibulum: report of a case. Arch Dermatol 1961;83:924-7. 2. Mehregan AH, Tumor of follicular infundibulum. Dermatolgica 1971;142:177-83. 3. Trunnell TN, Waisman M. Tumor of the follicular infundibulum. Cutis 1979;23:317-8. 4. Kossard S, Kocsard E, Poyzer KG. Infundibulomatosis. Arch Dermatol 1983;119:267-8. 5. Mehregan.zd-I. Infundibulartumors of the skin. J Cutan Pathol 1984;11:387-95. 6. Starink ThM, Cowden'sdisease:analysisof fourteen new cases. J AM ACADDF.RMATOL1984;11:1127-41. 7. Schnitzler L, Civatte J, Robin F, Demay CL. Tumeurs multiples de l'infundibulum pilaire avec drgrnrrescence baso-cellulare. Ann Dermatol Venereol 1987;114:551-6.