Introduction

Skin adnexal tumors (SATs) are the tumors arising from the appendages of the skin such as sweat glands, sebaceous glands and hair follicles. They are often difficult to diagnose clinically and histopathologically [1]. The diagnosis of skin adnexal tumors is sometimes complicated by their ability to produce cysts or because pigmented variants have been reported. Clinically, most skin adnexal tumors have similar gross presentation hence histopathology plays an important role in reaching the correct diagnosis [2]. Color, lobulation and variable induration can be clues in narrowing down the clinical diagnosis. Dermoscopy does not reveal pathognomonic features and Immunohistochemistry has limited value in diagnosis of adnexal tumors. IHC can be used in differentiating adnexal carcinoma from metastatic carcinoma as SATs show p63 and CK5/6 positivity. Because of these considerations, it is common to experience uncertainty in deciding whether a particular tumor is benign or malignant; in such casesit is appropriate to give a descriptive diagnosis such as ‘atypical skin adnexal tumors’ or ‘skin adnexal tumor of uncertain malignant potential’ along with a recommendation for complete excision and consideration of follow up. However, histopathology still remains the gold standard for the diagnosis of SATs as the clinical presentation is quite indistinctive since most of the tumors present as asymptomatic papules or nodules. Cytochemical stains such as PAS, mucicarmine, alcian blue, and reticulin may aid in establishing the diagnosis. PAS stain highlights the characteristic eosinophilic globules in a spiradenoma as well as the basement membrane material surrounding the nests of tumor cells and small round droplets in a case of cylindroma. Alcian blue stain helps in demonstrating the intense staining of the stroma in a case of chondroid syringoma.

Exact categorization of benign adnexal tumor are significant because it can give a clue to the association of internal malignancy like multiple trichilemmoma and breast carcinoma which is known as cowden’s syndrome [3]. Except in syndromic setting and a few additional sporadic entities with identified genetic mutations, not much is known about etiopathogenesis of adnexal tumors. UV radiation exposure and immunosuppression have been proposed as possible triggering factors.

The clinical presentation of these tumors is non-

Statistical Methods: The data were entered into MS Excel sheet and analysis was done using available options under MS Excel. Percentages were calculated.

Results

A total of 41 patients (22 males and 19 females) with adnexal tumour were included in the study. The male persons were more affected than females (Male to Female ratio was 1.15:1). Out of 41 cases, 36 (87.80 %) were benign while only 5 (12.20%) were malignant.

Table 1 shows that the sweat gland tumors accounted for 22 (53.65%) cases, sebaceous gland tumors 6(14.63%) cases and hair follicle tumors 14(24.40%) cases according to direction of differentiation

Table-1: Distribution of adnexal tumour according to histologic variation.

Table 2 shows that among the malignant tumours, sebaceous adenoma constitutes 5 cases and only one case of malignant proliferating tricholemmal tumour.

Table-2: Distribution of adnexal tumour according to sex.

proliferation likes sebaceous gland, sweat gland or hair follicle mass be considered [7]. The incidence of benign tumour was more as compared to malignant SAT.

In the present study 36 out of 41 cases were benign (87.80%) and only 5 cases (12.20 %) were found to be malignant. There were similar report found in the Prasad BVS et al which reported 93.75% benign and 6.25% malignant cases[4]. Similar findings were observed by other studies conducted by Kaur K et al, Valand AG et al ,Sharma A et al study and Radhika K respectively [2,8–9].

The present study showedthat majority of the adnexal tumours was present in the age group of 40-60 years and male being more than female as 22 were male out of total 41 cases. Similar findings were observed in the studies done by Rajalakshmi V et al and Kaur K et al [8,11,].While in contrast Arora A et al study showed that the most common age group affected by the tumour was between 20- 40 years and predominantly occurred in females compared to males [12].

The ratio of male to female ratio was more as the ratio was 1.15:1in the present study. The study done by Nair PS et al showed that the male to female ratio was 1:2.3 and the study by Pantola C et al found ratio of 1.8:1 [13,14]. The most common anatomical site found to be head and neck region (53%) which was 22 out of 41 cases. Similar findings were observed by other studies conducted by Prasad BVS et al , Arora A et al, Gandhi R et al and Kaur K et al study[4,12,3,8].

Majority of adnexal tumour was present as fleshy colour, multiple papules or solitary nodules [15,16]. Tumour arising from sweat gland were found to be very dominant. Out of 41 cases, 22 cases (53%) of sweat gland tumours were diagnosed in the present study. Similar finding were observed in the study conducted by Pantola C et al, Pujani M et al and Prasad BVS et al study respectively [4,14,17]. Another study conducted by Suri Jet al showed pilomatricoma (hair follicle tumour)to be the most common one [18]. The Pilomatricoma tumour in the present study showed dermal proliferations of irregular tumour island and intervening stroma. It comprised of two type of cells that is basaloid cells and shadow (ghost) cells. The basaloid cells were seen in the periphery of the tumour and centre of the island was occupied by shadow cells, having eosinophilic cytoplasm, distinct cell border and no nuclear staining (Figure 1).

The present study showed nodular hidraadenoma to be the commonest sweat gland origin tumour Figure-1 showed that 40-year-old female having frontal swelling at the base of nose with solitary nodule which was 0.5-2 cm, firm in consistency, slightly mobile since last 4months. It was diagnosed as nodular hidradenoma by microscopy. Microscopic picture revealed well circumscribed dermal nodule showing island of basaloid cells, round to oval nucleus and basophilic cytoplasm with few clear cells, having clear or eosinophilic cytoplasm. Cells were arranged in solid area with duct like structure and scanty cystic changes (Figure 2).

Fig-2: A: 40-year female presented with frontal swelling of base of Nose. B: 10x shows nodular hidradenoma. C: 40x shows nodular hidradenoma constituted of basaloid cells and clear type of cells.

Two cases of Trichoepithelioma found in head and neck. Microscopically revealedwell circumscribed comprising of island of basaloid cells with hair follicle differentiation in a cellular stroma small focus of calcifications. But no retraction artifact identified in the stroma(Figure 4). Whereas two cases of Trichoepithelioma were reported in Sharma A et al study and three cases of Trichoepithelioma were reported by Suri J et al and Sahu A et al study [1,9,18].

Fig 4: A: 10 X Shows Trichoepithelioma. B: 40x Shows Multiple clusters of basaloid cells arising from basal layer of epidermis and proliferating towards dermis layers.

A total number of five malignant adnexal tumour was found, out of which one case of malignant proliferating tricholemmal tumour was found in head and neck region in a 43 years male patient and one case of sebaceous carcionoma also diagnosed as scalp nodule in a 57 years male patient and three cases of mammary pagets disease were diagnosed as malignant adnexal tumour in the age group of 50-60 years.

Pagets disease of nipple revealed breast tissue with nipple areola region and basal layer of epidermis showing pigments and clusters of vacuolated cells.

Fig 6: A: 10x Shows Sebaceous Carcinoma. B: 40x Shows Malignant Sebaceous glands

The study done by Kaur K et al found sebaceous carcinoma was common malignant adnexal tumour (19.64%) and the common age group was more than 60 years of age [8]. The Sebaceous Carcinoma characterized by tumour cells which showed irregular epithelial lobules with an infiltrating growth pattern in the dermis.

These tumour cells comprised island of sebaceosus gland with high N: C, nucleoplemorphism, atypical mitotis and vaculolated cytoplasm (Figure 6).

As per the recent guidelines and classification of WHO skin tumour and the pagets disease of nipple have been included in the study

Limitation of the present study: IHC has been done according to the availability in the institute.

Conclusion

The present study of skin adnexal tumour indicated that majority of such type of tumour are benign in nature and only few cases of malignancy has been observed. The predilection of such tumor is predominantly head and neck region followed by extremities and chest and the common age group was between 4^th-6^th decades and have predilection for males.

Skin adnexal tumour was always challenging because of its nonspecific and overlapping clinical features, few of them specially the malignant one can easily mimic clinically and grossly with various soft tissue sarcoma like MFH (Malignant fibrous histiocytoma) or sarcoma with rhabdoid differentiation.

Therefore, histopathology is a gold standard to diagnose dermal adnexal tumor. The single centre study could help us to know the characteristics of adnexal tumour in hospital based population of southern region of Rajasthan.

What this study adds to the existing knowledge?

Five rare cases of malignant adnexal tumour were observed out of which pagets disease of nipple and sebaceous carcinoma were rare identities. Immunohistochemistry marker was used in the cases of pagets disease of nipple.

6. Santa Cruz DJ. Tumors of the skin, In- Fletcher CD, editor, Diagnostic Histopathology of Tumors. 3rd ed, Philadelphia- Churchill Living Stone Elsevier. 2007,Vol(2)1423-1526.
7. Pantola C, Kala S, Agarwal A, Amit S, Pantola S. Cutaneous adnexal tumours- A clinicopathological descriptive study of 70 cases. World J Pathol. 2013;2;77-82.
8. Fulton EH, Kaley JR, Gardner JM. Skin Adnexal Tumors in Plain Language A Practical Approach for the General Surgical Pathologist. Arch Pathol Lab Med. 2019;143(7)832-851.
9. Kaur K, Gupta K, Hemrajani D, Yadav A, Mangal K. Histopathological analysis of skin adnexal tumors- A three-year study of 110 cases at a tertiary care center. Indian J Dermatol. 2017;62(4)400-406.
10. Sharma A, Paricharak DG, Nigam JS, Rewri S, Soni PB, Omhare A, et al. Histopathological study of skin adnexal tumours-Institutional study in South India. J Skin Cancer. 2014;4;543756.
11. Radhika K, Phaneendra BV, Rukmangadha N, Reddy MK. A study of biopsy confirmed skin adnexal tumours- experience at a tertiary care teaching hospital. J Clin Sci Res. 2013;2(3);132-138.
12. Suri J, Mahajan D, Koul KK, Kumari R. A Clinicopathological Analysis of Skin Adnexal Tumours- Four Year Retrospective Study. JK Sci. 2016;18(4)248-251.