Clinico-dermatoscopic study of seborrheic keratosis from a rural tertiary care centre of western India :Pragya A Nair, Namrata Bhavsar, Dhruv Patel, Pigment International

ORIGINAL ARTICLE
Year : 2020 | Volume : 7 | Issue : 2 | Page : 69--74

Clinico-dermatoscopic study of seborrheic keratosis from a rural tertiary care centre of western India

Pragya A Nair, Namrata Bhavsar, Dhruv Patel
Pramukshwami Medical College, Karamsad, Gujarat, India

Correspondence Address:
Dr. Pragya A Nair
Department of Dermatology & Venereology, Pramukshwami Medical College, Karamsad 388325
India

Abstract

Background: Seborrheic keratosis is a benign papilloma of the skin having different clinical variants. A dermatoscope is used to reach to the correct diagnosis without going for any interventional investigation like biopsy, thus the study was done to correlate clinical and dermatoscopic findings in seborrheic keratosis. Material and Methods: It was an observational study conducted after permission from ethics committee. Patients diagnosed clinically as seborrheic keratosis were enrolled over a period of 6 months. Detail history and examination were done based on pre-structured proforma. Dermatoscopy was done from randomly selected lesions and images were captured and stored in laptop. Descriptive statistics was calculated for patterns of various changes. Results: Total 51 patients were clinically diagnosed as seborrheic keratosis, with maximum in the age ranging from 51 to 70 years. Sex ratio was equal with positive family history in 68.6%. Total 298 lesions were found of which, maximum were on the face in 56.37%. Commonest variant seen was CSK in 50.67% lesions. Comedone like opening was the most common dermoscopic pattern in 66.44% lesions followed by sharp demarcation in 55.70% and fissures and ridges in 53.69% lesions. Conclusion: Seborrheic keratosis was more commonly seen in elderly, with CSK as commonest variant and comedone like opening as most common dermatoscopic pattern in our study.

How to cite this article:
Nair PA, Bhavsar N, Patel D. Clinico-dermatoscopic study of seborrheic keratosis from a rural tertiary care centre of western India.Pigment Int 2020;7:69-74

How to cite this URL:
Nair PA, Bhavsar N, Patel D. Clinico-dermatoscopic study of seborrheic keratosis from a rural tertiary care centre of western India. Pigment Int [serial online] 2020 [cited 2023 Mar 30 ];7:69-74
Available from: https://www.pigmentinternational.com/text.asp?2020/7/2/69/302069

Full Text

Introduction

Seborrheic keratosis (SK) is a benign papilloma of the skin characterized by typical morphology and is considered as a characteristic sign of aged skin.[1] Various clinical variants of SK include common seborrheic keratosis (CSK), dermatosis papulosa nigra (DPN), pedunculated seborrheic keratoses, flat seborrheic keratoses and stucco keratosis.[2] The lesions of SK can occur at any site over the body, but are most frequently seen over the face and upper trunk. The lesions are usually asymptomatic, but may be itchy.[3]

SK presents as one of the most common cosmetic skin complaints, where it can sometimes clinically simulate a melanocytic lesion; therefore, dermatoscopy is needed to reach to the correct diagnosis without going for any interventional investigation like biopsy.[4]

The study was done to find the dermatosocpic patterns of seborrheic keratosis an correlate them clinically.

Materials and Method

This was an observational study conducted at our centre after permission from ethics committee between period of September 2017 to February 2018. A total of 51 patients diagnosed clinically as seborrheic keratosis were enrolled over a period of 6 months. Detail history was taken based on pre structured proforma. Factors such as age, sex, age of onset, duration, site and number with colour and morphology of lesions were recorded. Dermoscopy was done with firefly Pro DE 300 under 10X magnification using both polarised and non polarised light. Lesions for dermoscopic examination were selected randomly. The dermoscopic criteria for seborrheic keratosis was used.

Dermatoscopic images were captured, recorded and stored in laptop.

Descriptive statistics (mean, standard deviation, proportions, frequencies) were calculated for depicting the patterns of various changes observed.

Results

Total 51 patients were clinically diagnosed as seborrheic keratosis, with maximum in the age ranging from 51 to 70 years [Table 1]. Sex ratio was equal with 24 (47.06%) males and 27 (52.94%) females. Family history was positive in 35 (68.6%) patients. SK were asymptomatic in 98.8% of cases and only1.2% had complain of itching.{Table 1}

Total 298 lesions were found in 51 patients of SK. Maximum 168 (56.37%) lesions were on the face followed by 45 (15.10%) over trunk [Table 2]. Commonest variant seen was CSK in 151 (50.67%) lesions followed by 73 (24.49%) presenting with DPN [Table 3][Figure 1].{Table 2}{Table 3}{Figure 1}

Verrucous surface was found in 180 (60.40%) [Figure 2]a followed by flat topped [Figure 2]b surface in 85(28.5%) and macular surface in 33 (11.07 %)lesions. Most of the SK were black colored 199(66.7%) [Figure 2]c, followed by dark-brown 78(26.1%), and grey in 21 (7.05%).{Figure 2}

Comedone like opening (CLO) was the most common dermoscopic pattern in 198(66.44%) [Figure 3]a lesions followed by sharp demarcation (SD) in 166 (55.70%) and fissures and ridges (FR) in 160(53.69%) lesions [Table 4].{Figure 3}{Table 4}

Discussion

Seborrheic keratoses (SK) are the most common benign epidermal tumors, usually occurs in middle-aged individuals.[5]

The frequency of SK appears to increase with age. In our study maximum incidence of SK was seen during 51-60 years of age group in 25.49% cases. Other studies also showed peak incidence in 31–50 years (42%)[6] and above 60 age group with 40% cases.[7]

A slight female predominance was seen in our study with 52.94% as also seen by Alapatt et al.[6] with 76% and Rajesh et al.[7] with 51.2%, otherwise gender distribution is equal.[8] The reason behind it may be more cosmetic concern in females about the lesions over exposed areas of face.

Seborrheic keratosis were asymptomatic in 98.8% of cases and only1.2% had itching in our study almost same as Rajesh et al.[9] while in study by Alapatt et al.[6] 26% had itching. Genetics and Sun exposure have been implicated as the major causes for development of SK.[9] Considering trunk, back & lower limbs as totally sun-protected areas, 72.4% lesions were in sun exposed areas in our patient, while family history was positive in 68.6%patients.Findings were in comparision to a study conducted in Korean males by Kwon et al.[12] on 303 volunteers aged 40–70 years, which showed cumulative Sunlight exposure to be a contributing factor. Study by Alapatt et al.[6] reported positive family history in 62% cases while sun exposure was not seen to be a major factor as 62% of their patients had lesions in covered areas such as chest, abdomen, back, thighs, and legs.

Sk begin as well-circumscribed, dull, flat, tan, or brown patches with pseudohorn cyst & as they grow, become more papular, taking on a waxy verrucous or “stuck on” appearance. Most of the SK in our study were black colored in 66.7% followed by dark-brown 26.1% and grey in 7.05% cases. Rajesh et al.[7] in their study found black colored SK in 79.6% dark-brown in 34.4% and grey in 9.2% cases. Our study showed most lesions of SKs with verrucous surface in 60.40% followed by flat topped surface in 28.5%and macular surface in 11.07 % lesions. In the study by Rajesh et al.[7] verrucous surface was found in 77.2%, flat topped in 26.4% and macular in 6.4%surface with one patient having “raindrop pattern” on back.

In our study out of 298 SK, 50.67% were CSK followed by 24.49% DPN almost same as reported by Alapatt et al.[6] with 46% CSK followed by 26% DPN. They reported higher incidence of stucco keratoses (18%) compared to pedunculated variety (10%) while in our study 11.74% lesions were pedunculated SK & 4.02% were stucco Keratosis. A study conducted in South India by Rajesh et al.[7] has reported CSK being the most common (60%), followed by DPN (46.6%), pedunculated SK (21.2%), and stucco keratoses (2%). Abdel-Azim et al.[11] study also showed the highest incidence of CSK (46%) followed by DPN (26%), stucco keratoses 18% and pedunculated (10%)

The classic dermatoscopic criteria for SK (ML cyst and CLO) have a high prevalence but the use of additional dermatoscopic criteria, such as fissures, hairpin blood vessels, sharp demarcation, and moth-eaten borders, improves the diagnostic accuracy. The proper identification of pigment network and network-like structures is also important for the correct diagnosis.[10]

CLO are ‘black head like’ plugs of brown to black color which corresponded to papillomatosis .ML cysts are round, whitish, or yellowish structures, corresponded to horn cysts.[14] Fissures are irregular linear keratin-filled depressions, it corresponds to papillomatosis in histopatholog . FP-like structures are thin, brown, parallel lines resembling FPs. ME border is the concave border of the SK which has been compared to ME garment. HP blood vessels correspond to long capillary loops, mainly found at the border of SK. SD is the abrupt cut-off of the pigmented border. NL structures are grid-like or honeycomb-like structures resembling a pigment network of melanocytic lesions.[3],[4] corresponded to pigmentation

CSK appear on hair-bearing surfaces, predominantly on the head, trunk, and neck. They present as sharply demarcated, brown, “stuck on” papules with velvety or granular surfaces, and are uniformly tan to dark brown.[2]

In our study with 151 lesions of CSK, CL opening was found in 75.49%, FR in 46.66%, ML cyst in 26.49%, network like structure in 5.30%, moth eaten border in 33.77%, & sharp demarcation in 78.14% lesions. Study done by Alapatt et al.[8] also showed the most common dermoscopic findings seen in CSK as CL openings (78.3%), FR (60.9%), ML cysts (60.9%), while less common findings were SD (56.5%), NL structures (43.5%), ME border (39.1%), and FP structures (13%), while study by Rajesh et al.[9]showed dermoscopic findings in CSK (n = 150) as CL (80%), SD (82.6%),and FR (78.58%) and less common findings were ME (31.3%), ML (24%), and NL (4%).

DPN are very common among blacks and manifests at earlier ages than CSK. It is more common among women & presents as multiple 1-5 mm large black papules over the face, neck, chest, and upper back. Positive family history is common.[2]

DPN showed only three dermatoscopic findings, i.e. CL (85.3%), FR (78.4%) and SD (17 .2%).[9]Alapatt et al.[8] also found FR and CL openings (92.3%) followed by SD in 69.2% of the cases & NL structures and ME borders were seen in only 7.7% of the cases with DPN. Our study also showed 80.82% with CL opening, 75.34% with FR & 21.92% with sharp demarcation in 73 lesions of DPN.

Pedunculated seborrheic keratoses present as brown to black, pedunculated papules, of size 1-5 mm, most commonly in areas of friction, commonly seen on neck and axillae. Of 35 lesions with pedunculated SK in our study, 57.14% had CL opening & 100% had FR similar to other studies.[6],[7]

Flat seborrheic keratoses are benign lesions that typically appear as oval tan-brown patches or macules on sun-exposed areas of the skin, especially on the face, backs of the hands and wrists, extensor surfaces of the forearms, and chest. They are asymptomatic and increase with the age. Of 27 lesions of Flat SK, 18.52% had CL opening, 77.78% NL pattern & 74.07% with SD which is in contrast to study by Rajesh G et al showing NL in 88.8%, SD in 74%, FP like structures in 55.5%), and CL in 11%.[7]Stucco keratoses presents with white or gray-white verrucous papules are a few millimeters in size, often in large numbers on sun-exposed areas more common in men, and are relatively easily scratched off.

Of 12 lesions of stucco keratosis 91.66% had NL, 33.33% moth eaten border & 100% with SD in our study comparable to other studies which showed NL & SD as the characterstics dermatoscopic finding for stucco keratosis.[8],[9]

Braun et al.[4] evaluated 203 pigmented SK and found high prevalence of classic dermoscopic criteria of SK, i.e., CL openings (70%) and ML cysts (66%). They suggested four other dermoscopic criteria [fissures (61%), HP blood vessels (63%), SD (90%) and ME border (46%)] which they considered would improve the diagnostic accuracy and reduce the misclassification into melanocytic lesions. They also suggested that NL structures should not be confused with the typical pigment network as seen in melanocytic lesions.

Kopf et al.[13] identified “fat fingers” (thick digitate linear, curvilinear, branched, or oval/circular dermoscopic structures typically seen in SK where they represent the gyri of their cerebriform surfaces) in 44% of the lesions after examining 299 SK and suggested that identification of these structures can be very helpful in the dermoscopic diagnosis of SK, especially when the classic features of SK are absent.

We could not see HP blood vessels in any of our cases similar to other Indian studies,[6],[7] may be due to Indian skin type 4 & 5 in majority of patients where blood vessels can not be seen through the brown-color of Asian skin. HP blood vessels are seen in study by Braun et al.[10] & Abdel-Azim et al.[13] in 63%, 2.9% lesions respectively .

Conclusion

SK appears to be more common in middle- and old-aged, with almost equal sex distribution, predominantly affecting the face, back, and trunk. The most common clinical variant was CSK & CL the commonest dermatoscopic pattern. Dermoscopy is a useful tool to confirm the diagnosis of SK with specific pattern in particular variant.

Limitations

We could not do dermatoscopy & histopathological correlation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1	Pierson D, Bandel C, Ehrig T et al. Benign epidermal tumors and proliferations. In: Bologna JL, Jorizzo JL, Raphini RP et al. eds Dermatology. Toronto, Canada: Mosby 2002. 1697-1717
2	Noiles K, Vender R. Are all seborrheic keratoses benign? Review of the typical lesion and its variants. J Cutan Med Surg 2008: 12:203-210.
3	Reiches AJ. Seborrheic keratoses; are they delayed hereditary nevi? AMA Arch Derm Syphilol 1952;65:596‑600.
4	Roberti V, Devirgiliis V, Curzio M, Gobbi S, Coppola R, Calvieri S, Panasiti V. The blue globular pattern in dermoscopy. Dermatology 2013;226:260-266.
5	Mackie RM, Quinn AG. Non-melanoma skin cancer and other epidermal skin tumours. In: Burns T, Breathnach S, Cox N, Griffiths C, editors. Rook’s Textbook of Dermatology. 7th ed. Oxford: Blackwell Publishing; 2004. 36. 1-36. 50.
6	Alapatt GF, Sukumar D, Bhat MR. Aclinicopathological and dermoscopic correlation of seborrheic keratosis. Indian J Dermatol 2016;61:622-7.
7	Rajesh G, Thappa DM, Jaisankar TJ, Chandrashekar L. Spectrum of seborrheic keratoses in South Indians: A clinical and dermoscopic study. Indian J Dermatol Venereol Leprol 2011 77:483‑8
8	Zhang RZ, Zhu WY. Seborrheic keratoses in five elderly patients: An appearance of raindrops and streams. Indian J Dermatol 2011;56:432‑4. [6]
9	Thomas VD, Swanson NA, Lee KK. Benign epithelial tumours,hamartomas and hyperplasias. In: Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell D, editors. Fitzpatrick’s Dermatology in General Medicine. 8th ed. New York: McGraw‑Hill; 2012. p. 1319‑36.
10	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.
11	Abdel-Azim AA, Ahmed NA, Hamid GDA, Abdel Moaty NT. Role of dermatoscope in diagnosing and differentiating different types of seborrheic keratoses. Egypt J Dermatol Venerol 2015;35:75-81
12	Takenouchi T. Key points in dermoscopic diagnosis of basal cell carcinoma and seborrheic keratosis in Japanese. J Dermatol 2011;38:59-65.
13	Kopf AW, Rabinovitz H, Marghoob A, Braun RP, Wang S, Oliviero M et al. “Fat fingers:” a clue in the dermoscopic diagnosis of seborrheic keratoses. J Am Acad Dermatol 2006;55:1089-91.Rajesh, et al. Spectrum of SK in south Indians
14	Elgart GW. Seborrheic keratoses, s;olar lentigines, and lichenoidkeratoses. Dermatoscopic features and correlation to histology and clinical signs. Dermatol Clin 2001;19:347‑57.