Indian J Sex Transm Dis Indian J Sex Transm Dis
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Year : 2017  |  Volume : 38  |  Issue : 2  |  Page : 176-179

Giant seborrheic keratosis of the genitalia with an unusual histopathological finding

Department of Skin and STD, Vinayaka Mission's Kirupananda Variyar Medical College and Hospital, Salem, Tamil Nadu, India

Date of Web Publication23-Oct-2017

Correspondence Address:
Ganga Vellaisamy Seethalakshmi
No 11, Mullai Nagar, Near Chandra Mahal, Seelanaickenpatty, Salem - 636 201, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijstd.IJSTD_95_16

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Seborrheic keratosis (SK) of the external genitalia is a rare entity which can be easily misinterpreted as genital warts. Histopathology is a useful tool to make a diagnosis in such cases. We report a 62-year-old male who presented with multiple polypoidal lesions exclusively on the external genitalia. Histopathology was suggestive of hyperkeratotic type of SK which showed some unusual features.

Keywords: Genital seborrheic keratosis, hyperkeratotic seborrheic keratosis, polypoidal genital mass

How to cite this article:
Seethalakshmi GV, Venugopal S, Nanjappachetty G, Kannan G. Giant seborrheic keratosis of the genitalia with an unusual histopathological finding. Indian J Sex Transm Dis 2017;38:176-9

How to cite this URL:
Seethalakshmi GV, Venugopal S, Nanjappachetty G, Kannan G. Giant seborrheic keratosis of the genitalia with an unusual histopathological finding. Indian J Sex Transm Dis [serial online] 2017 [cited 2023 Nov 28];38:176-9. Available from:

   Introduction Top

Seborrheic keratoses (SKs) (senile warts, basal cell papillomas) are common, often multiple, benign tumors which usually first appear in middle life.[1] SK can develop on the face, neck, and trunk (especially the upper back) as well as the extremities. SK can occur in the genital region which is a rare entity that can be easily misdiagnosed as genital warts, and the differentiation is only made on histopathology. We are reporting a rare and unusual case of SK with multiple giant polypoidal lesions restricted to the skin on and around the genitalia along with unusual histopathological features.

   Case Report Top

A 62-year-old male presented with multiple asymptomatic polypoidal growths on the penis and groin region of 1 year duration. The lesion started as a small pigmented papule on the right side of groin which gradually increased in size to involve the entire external genitalia involving the groin bilaterally, around the base of penis and ventral aspect of shaft of penis.

Dermatological examination showed multiple pigmented polypoidal masses of varying sizes in the external genitalia involving the groin bilaterally, around the base of penis and ventral aspect of shaft of penis [Figure 1]. The scalp and oral mucosa were normal. There was no associated lymphadenopathy. We considered differential diagnosis of condyloma acuminata, giant SK, and acrochordons (Skin tags). Routine laboratory tests were within normal limits. Complete surgical excision of the lesions was done. Gross examination revealed a pigmented, friable mass.
Figure 1: Multiple pigmented polypoidal mass over the pubis, penis, scrotum and groin

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Histopathological examination showed hyperkeratosis, acanthosis, and papillomatosis [Figure 2] and [Figure 3]. Numerous digitate upward extensions of epidermis-lined papillae resembling church spire were seen [Figure 4]. Both true horn cysts and pseudo horn cysts [Figure 5] were seen. The epidermis consists mainly of squamous cells [Figure 6] along with excess amount of melanin dispersed throughout the epidermis [Figure 7] which is an unusual finding in hyperkeratotic SK. Based on the clinical and histopathological findings, a diagnosis of hyperkeratotic type of SKs was made. On further follow-up, patient recovered well [Figure 8].
Figure 2: Photomicrograph showing hyperkeratosis, papillomatosis, and horn cyst (H and E, ×40)

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Figure 3: Photomicrograph showing hyperkeratosis, papillomatosis, and horn cyst (H and E, ×100)

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Figure 4: Photomicrograph showing church spire appearance (H and E, ×100)

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Figure 5: Photomicrograph showing a pseudo horn cyst (H and E, ×100)

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Figure 6: Photomicrograph showing plenty of squamous cells (H and E, ×100)

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Figure 7: Photomicrograph showing excess amount of melanin dispersed throughout the epidermis (H and E, ×100)

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Figure 8: After 2 months of surgical excision

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   Discussion Top

SK is a benign tumor, frequently pigmented, more common in the elderly and composed of epidermal keratinocytes.[2] Most lesions are no more than a centimeter or so in diameter, but larger variants, sometimes even pedunculated, have been reported. Classically, SK tends to increase with the age in number.[2] The lesions are more common in the sun-exposed areas. Several morphologic forms of SK are described-flat SK, pedunculated skin tag-like, stucco keratosis, dermatosis papulosa nigra, melanoacanthoma, and inverted follicular keratosis.[2],[3] Rare clinical variants include a familial form, which may be of early or late onset, and a halo variant with a depigmented halo around each lesion.[4]

The nature of SK is still disputed. A follicular origin has been proposed. They have also been regarded as a late-onset nevoid disturbance or the result of a local arrest of maturation of keratinocytes.[5] Human papillomavirus has been detected in a small number of cases, particularly from the genital region.[6] Endothelin-1, a keratinocyte-derived cytokine with a stimulatory effect on melanocytes, is thought to be involved in the melanization of SKs.[7]

At least nine distinct histological patterns have been recognized: acanthotic (solid), reticulated (adenoid), hyperkeratotic (papillomatous), clonal, irritated, inflamed, desmoplastic, adamantinoma, and with pseudorosettes.[8] Overlapping features are quite common. All types of SK have in common hyperkeratosis, acanthosis, and papillomatosis. The acanthosis in most instances is due entirely to upward extension of the tumor. Thus, the lower border of the tumor is even and generally lies on a straight line that may be drawn from the normal epidermis at one end of the tumor to the normal epidermis at the other end.

The acanthotic type appears to be the most common type which shows marked acanthosis of predominantly basaloid cells.[3] Moderate papillomatosis and hyperkeratosis are present and characteristic horn cysts, pseudo horn cysts are seen. Approximately one-third of these lesions exhibit melanocyte proliferation and hyperpigmentation demonstrating the common finding of overlapping histologic findings between different subtypes. Squamous eddies are absent.

Irritated type shows a lichenoid inflammatory infiltrate in the dermis and intraepidermal squamous eddies, which are composed of whorling aggregates of eosinophilic squamous cells.[3] In this type, the squamous cells outnumber the basaloid cells. Adenoid type is characterized by numerous, thin, double rows of basaloid epidermal cells which extend from the epidermis and show branching and interweaving in the dermis. Hyperpigmentation is relatively common although horn cysts and pseudo horn cysts are not seen.[3] Clonal type is characterized by proliferation of sharply demarcated intraepidermal nests of basaloid cells (Borst-Jadassohn phenomenon).

In the hyperkeratotic type, also referred to as the digitate or serrated type, pronounced papillomatosis is present.[3] Acanthosis is mild but shows a verrucous appearance with elongated projections (“church spire” pattern) which is seen in our case. There is pronounced ortho-hyperkeratosis along with squamous cells throughout the epidermis. While horn cysts and pseudo horn cysts may be seen, they are less common than in the acanthotic form. As a rule, no excess amounts of melanin are found.[9] However, in our case, melanin was present throughout the epidermis.

Melanoacanthoma is a rare variant of pigmented SK showing a marked increase in the concentration of large and richly dendritic melanocytes throughout the tumor lobule. Apart from histopathology, dermoscopy is a reliable alternative tool in the diagnosis of SK. The most common dermoscopic features of cutaneous SK are comedo-like openings and milia-like cysts.[3],[10] Other features include fissures, hairpin vessels, sharp demarcation, and moth-eaten borders.[10]

   Conclusion Top

This case report presented a rare form of SK which affected the external genitalia exclusively. We are presenting this case for its unusual histopathological finding. To the best of our knowledge, this happens to be the first case of hyperkeratotic type of SK with increased melanin pigmentation throughout the epidermis.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Yeatman JM, Kilkenny M, Marks R. The prevalence of seborrhoeic keratoses in an Australian population: Does exposure to sunlight play a part in their frequency? Br J Dermatol 1997;137:411-4.  Back to cited text no. 1
Quinn AG, Perkins W. Non-melanoma skin cancer and other epidermal skin tumours. In: Burns T, Breathnach S, Cox N, Griffiths C, editors. Rook's Textbook of Dermatology. 8th ed., Vol. 3. Oxford: Blackwell Science; 2010. p. 52.38-52.39.  Back to cited text no. 2
Hafner C, Vogt T. Seborrheic keratosis. J Dtsch Dermatol Ges 2008;6:664-77.  Back to cited text no. 3
Migally M, Migally N. Halo seborrheic keratosis. Int J Dermatol 1983;22:307-9.  Back to cited text no. 4
Sanderson KV. The structure of seborrhoeic keratoses. Br J Dermatol 1968;80:588-93.  Back to cited text no. 5
Leonardi CL, Zhu WY, Kinsey WH, Penneys NS. Seborrheic keratoses from the genital region may contain human papillomavirus DNA. Arch Dermatol 1991;127:1203-6.  Back to cited text no. 6
Teraki E, Tajima S, Manaka I, Kawashima M, Miyagishi M, Imokawa G. Role of endothelin-1 in hyperpigmentation in seborrhoeic keratosis. Br J Dermatol 1996;135:918-23.  Back to cited text no. 7
Wade TR, Ackerman AB. The many faces of seborrheic keratoses. J Dermatol Surg Oncol 1979;5:378-82.  Back to cited text no. 8
Kirkham N. Tumors and cysts of the epidermis. In: Elder DE, Elenitsas R, Johnson BL, Murphy GF, editors. Lever's Histopathology of the Skin. 10th ed. Philadelphia: Lippincott Williams and Wilkins; 2009. p. 795-9.  Back to cited text no. 9
Braun RP, Rabinovitz HS, Krischer J, Kreusch J, Oliviero M, Naldi L, et al. Dermoscopy of pigmented seborrheic keratosis: A morphological study. Arch Dermatol 2002;138:1556-60.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]

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