B Mishra,DP Mishra,S Choudhury MKCG Medical College, Berhampur.Address For Correspondence:Dr Bandana Mishra, Asst. Prof, Dept. Of Pathology, MKCG Medical College, Berhampur.ABSTRACT: Background: Skin adenexal tumors are large and diverse group of skin tumors that are classified according to embryologic and histologic features into sweat gland tumors (eccrine, apocrine), follicular and sebaceous. Usually they are rare tumors, clinically misdiagnosed, histology helps in establishing the diagnosis . Aim: To study histopathology of skin adnexal neoplasms and to correlate with the clinical profile. Materials and Methods: Prospective & retrospective study was conducted in the Department of Pathology MKCG Medical College over a period of 5 years. Total 31 cases were included, diagnosed to have Skin adnexal neoplasm and confirmed by histopathology. All the specimens were formalin fixed, processed and stained with H&E and special stains wherever necessary. Tumors with follicular differentiation constituted the maximum number, 15 cases(48.4%) followed by eccrine tumor 13cases(42%);tumours of apocrine differentiation 3 cases(9.6%). Conclusion: Cutaneous adnexal neoplasms are relatively uncommon neoplasm with distinct histological features, commonly distributed in head and neck region, with slight male predominance in our study.Keywords:Cutaneous adnexal tumor, Histopathology, SAT (Skin adnexal tumor).INTRODUCTION: Cutaneous adnexal neoplasms are a large and varied group of neoplasms which differentiate towards pilosebaceous apparatus, apocrine and eccrine sweat glands 1–3. However, the apparent differentiation is not always distinct and some tumors can display elements of mixed differentiation. These divergences can be due to their origin from pluripotent stem cells 1–4. Usually SATs present as papules and nodules usually solitary lesion, but have distinct histological features 1–5. Most SATs are benign. However, diagnosing them may have important implications as they might be markers for syndromes associated with internal malignancies, such as trichilemmomas in Cowden’s disease and sebaceous tumours in Muir –Torre syndrome 1–3. Malignant tumors are rare, aggressive, have the potential for nodal involvement and distant metastasis with a poor clinical outcome 1–4. Therefore, establishing the diagnosis of malignancy in SATs is important for therapeutic and prognostic purposes. In this study we have analysed the frequency, clinical features, gross and microscopic features and the differentiating features between benign and malignant SATs. This study was undertaken to analyze the morphological ,clinical & histological features of Skin adenexal tumor at our center over a period of five years. MATERIALS AND METHODS:A combined prospective & retrospective study was done. Review of all skin adnexal neoplasms reported in the Department of Pathology, MKCG Medical College during the period January2013toDecember2017was done. 31 cases were there in total. Clinical detail of patients’ were documented including age, sex, clinical diagnosis & gross examination. The histopathological examination was done on formalin fixed tissues and paraffin embedded blocks. Haematoxylin &Eosin stained sections were examined and few special stains like PAS & reticulin were performed wherever required. All the slides were reviewed. The concordance of clinical and histopathological diagnosis was all so assessed.RESULTS: In the present study total 31 cases were found as skin adenexal tumor over a period of 5years. Majority of tumors were benign adnexal tumors, constituted 93.5% (29/31) cases and minority were malignant adnexal tumors, constituted 6.5% (2/31) cases ( Fig-1). The hair follicle tumors constituted the largest group involving 48.4% (15/31) cases followed by the sweat gland tumors 42 % (14/31) cases (Table 1). The hair follicle tumors are comprised of 10 proliferating trichilemmal cysts, 3cases of pilomatrixoma, trichoepithelioma 1 case, trichofolliculoma1case. The sweat glands tumors are comprised of nodular clear cell hidradenoma 7 cases, chondroidsyringoma 4 cases, apocrine hidrocystoma 2 cases, and syringocystadenomapapilliferum one case.. Amongst the benign tumors; proliferating trichilemal cyst (32.3%, 10/31) and clear cell hidradenoma(22.6%,7/ 31) were the most common tumors. Amongst the malignant tumors,malignant hydradenoma and malignant poroma were the only malignant tumors observed with one case each. The frequency distribution of various lesion is shown inTable-1.The head and neck region was the most common site affected (77.4 %, 16/31) followed by extrimities.(Table-2).The age of patients’ varied from 8years to 79 years. However, the highest incidence was observed in the age group of 41-50 years (25.8%, 8/31) (Fig-2). Considering sex , male preponderance was seen. The male -to- female ratio was 1.07:1 . Fig-1 Table – 1 : Benign skin adnexal tumors with frequency distributionAppenndageal tumors Benign tumor types number of cases(%)Hair follicle (48.4%) Trichilemmal cyst 10( 32.3% ) Pilomatrixoma 3(9.6% ) Trichofolliculoma 1( 3.2%) Trichoepithelioma 1( 3.2%)Sweatgland (45.2%) Nodular hidradenoma 7(22.6% ) Condroid syringoma 4(12.9% )Apocrine Apocrine hidrocystoma 2( 6.4%) Syringo cystadenomapapillifeerum 1(3.2% )————————————————————————————————————– Table – 2: Site Distribution of adenexal tumors.Head and Neck 24 (77.4 % )Extremity 05 (16.1% )Back 01 (3.2% )Genitalia 01 (3.2% ) Fig-3 Photomicrograph of Proliferating Trichilemmal cyst showing cyst lined with irregular lobules of proliferating squamous epithelium.Epithelium abruptly merge in to central portion of lobule.Cyst containing amorphous keratin. (H&E ,X 100)was the most common tumor in our study ,10 out of 31(32.3%).Fig-4 (A)Photomicrograph of Nodular Hidradenoma showing multinodular solid and cystic proliferations of adenexal keratinocytes.(H&E, X40), (B)Photomicrograph showing centre clear cells surrounded by dark keratinocytes.(H&E, X400)DISCUSSION: 1,7 Incidence of benign skin adenexal tumors is more as compared to malignant cases. Cutaneous adenexal tumors are said to differentiate towards different adnexal cell lines : hair follicle,sebaceous glands,ecrine glands,apocrine sweat glands. They can also differentiate towards more than one cell line in the same tumor. This could probably be due to their origin from pluripotent stem cells 1–4. In our study there was differentiation towards single cell line only. Even though most SATs are benign, malignant forms definitely occur but the incidence of malignant tumours is low. Malignant tumors may be : carcinoma of sebaceous glands,ecrine gland,apocrine glands,rarely pilomatrical carcinoma,malignant proliferating trichilemmal cyst,and trichilemmal carcinoma. In the present study, 93.5 % tumors were benign and 6.5% tumors were malignant, which was also seen in studies of Radhika et al5. In our study there were two malignant tumours reported : malignant hidradenoma , malignant poroma. There are certain general characteristic differentiating features between benign and malignant SATs. Benign tumors show symmetry, vertical orientation with V-shape, uniform collection of epithelial cells with dense fibrotic stromal reactions around tumor cells and absence of necrosis, atypia and mitosis 1–4,6. Malignant SATs show asymmetry, horizontal orientation of tumor, irregular arrangement of cells with infiltration as well as necrosis, atypia and mitosis with diminished tumor associated sclerotic stroma. Tirumalee et al., have stressed the importance of examining under scanner view magnification to assess the silhouettes of SATs to differentiate benign and malignant tumors 7. In our study both the malignant tumors displayed asymmetry, horizontal orientation of tumor with lack of lobulation. Irregular arrangement of cells with infiltration, necrosis, atypia and frequent mitosis, with diminished tumor associated sclerotic stroma. Present study shows hair follicular differentiation as the predominant tumor. In some other studies, nodular hidradenoma is the predominant tumour5. Gayathri et al., in their study have described trichoepithelioma of hair follicular origin to be the predominant tumour 6. Our study had majority of hair follicular tumor . The location of skin adenexal tumor varies with the histologic type.Head & neck region is the most common location frequently encountered, other sites being axilla,trunk,legs etc.. Radhika et al observed that head and neck region was the most common site of occurrence, which was also noted in our study (77.4% in Table-2). The most common site of involvement were fonud to be head & neck region followed by extrimities.CONCLUSION:To summarise, cutaneous adnexal tumors are uncommon and they are not routinely encountered in the surgical pathology practice. Their clinical presentation is very nondescript and histopathology is the gold standard for diagnosis. Though the malignant SATs are rare, they are aggressive, and always it is important to look for malignant features and surgical margins before signing out the adnexal tumors.REFERENCES:1. Elder D, Elinistas R, Ragsdale BD. Levers Histopathology of the skin. 8 th ed. Philadelphia: Lippincott Williams and Wilkins; 1997. Tumours of the epidermal appendages. In:Elder D, ElinistasR,Jaworsky C, Johnson B Jr , editors; pp. 747–803.2. Obaidat NA, Alsaad KO, Ghazarian D. Skin adnexal neoplasms-part 1 :An approach to tumours of the pilosebaceous unit. J ClinPathol. 2007;60:129–44.3. Obaidat NA, Alsaad KO, Ghazarian D. Skin adnexal neoplasm-part 2: An approach to tumours of cutaneous sweatglands. J ClinPathol. 2007;60:145–59.4. Storm CA, Seykora JT. Cutaneous adnexal neoplasms. Am J ClinPathol. 2002;118:33–49.5. Radhika K, Phaneendra BV, Rukmangadha N, Reddy MK. A study of biopsy Confirmed skin adnexal tumours: experience at a tertiary care teaching hospital. J ClinSci Res. 2013;2:132–8.6. Gayathri SS, Ezhilvizhi A, Ashok kumar S. An analysis of skin appendageal tumours in South India. J of evol and den sci. 2012;1:907–12 Figure 7(a) Nodular hideradenoma1.