Adnexal tumours of the skin as markers of cancer-prone syndromes

Diagnostic Accuracy of GATA6 Immunostaining in Sebaceous Tumors of the Skin

The accurate diagnosis of skin adnexal neoplasms is sometimes challenging but is necessary because medical management and follow-up may differ between tumors. GATA6 transcription factor has been identified as a new marker of the upper folliculosebaceous compartment (lower infundibulum, junctional zone and isthmus, and upper sebaceous gland) in the human skin. We aimed to determine the diagnostic accuracy of GATA6 immunostaining to diagnose sebaceous tumors compared with that to diagnose other adnexal and nonadnexal cutaneous neoplasms. We conducted a retrospective, evaluator-nonblinded study comparing the reference standard (diagnosis by an expert dermatopathologist) with GATA6 immunostaining to identify sebaceous tumors in a cohort containing 234 different tumors. The GATA6 expression score was significatively higher in sebaceous than that in nonsebaceous tumors. In addition, tumors originating from the upper hair follicle showed positive results for GATA6 staining; however, they showed lower GATA6 expression scores. Detection of sebaceous tumors using GATA6 positivity had a sensitivity of 95.7% (95% confidence interval [95% CI], 85.8-99.2), specificity of 80.8% (95% CI, 74.5-85.8), positive predictive value of 55.6% (95% CI, 44.7-65.9), and negative predictive value of 98.7% (95% CI, 95.4-99.8). GATA6 showed similar sensitivity to adipophilin, the reference marker; however, the specificity of GATA6 was higher, as observed in a cohort of 106 tumors enriched in squamous cell carcinomas with clear-cell histology. In addition, GATA6 positivity was assessed in 39 sebaceous carcinomas and compared with epithelial membrane antigen (EMA), CK7, and androgen receptor (AR) staining results. Although CK7 staining displayed lower diagnostic performances, GATA6 staining showed comparable results as EMA and AR. Finally, we found GATA6 expression in skin metastases of gastrointestinal origin, whereas GATA6 was absent in metastases originating from breast or lung cancers. Overall, our work identified GATA6 immunostaining as a new diagnostic tool for sebaceous tumors.

Are clinicians successful in diagnosing cutaneous adnexal tumors? a retrospective, clinicopathological study

Background/aim

Cutaneous adnexal tumors (CAT) are rare tumors originating from the adnexal epithelial parts of the skin. Due to its clinical and histopathological characteristics comparable with other diseases, clinicians and pathologists experience difficulties in its diagnosis.We aimed to reveal the clinical and histopathological characteristics of the retrospectively screened cases and to compare the prediagnoses and histopathological diagnoses of clinicians.

Materials and methods

The data of the last 5 years were scanned and patients with histopathological diagnosis of CAT were included in the study.

Results

A total of 65 patients, including 39 female and 26 male patients aged between 8 and 88, were included in the study. The female to male ratio was 1.5, and the mean age of the patients was 46.15 ± 21.8 years. The benign tumor rate was 95.4%, whereas the malignant tumor rate was 4.6%. 38.5% of the tumors were presenting sebaceous, 35.4% of them were presenting follicular, and 18.5% of them were presenting eccrine differentiation. It was most commonly seen in the head-neck region with a rate of 66.1%. When clinical and histopathological prediagnoses were compared, prediagnoses and histopathological diagnoses were compatible in 45% of the cases. Most frequently, it was the basal cell carcinoma, epidermal cyst, and sebaceous hyperplasia identified in preliminary diagnoses.

Conclusion

Cutaneous adnexal tumors are very important, as they can accompany different syndromes and may be malignant. Due to difficulties in its clinical diagnosis, histopathological examination must be performed from suspicious lesions for definitive diagnosis.

Adnexal Tumors of Skin: An Experience at a Tertiary Care Center at Delhi

Background:

Adnexal skin tumors are a heterogeneous group of uncommon tumors usually misdiagnosed clinically due to a huge variety of types and their variants. Histopathology usually helps in establishing the diagnosis.

Aims:

The study was undertaken to analyze the morphological, clinical, and histological features of adnexal tumors (ATs) of the skin at our center over a period of 4 years.

Subjects and Methods:

retrospective study was conducted over a period of 4 years (April 2010–March 2014), comprising 25 ATs of skin diagnosed in the Department of Pathology, Hamdard Institute of Medical Sciences and Research, Jamia Hamdard, New Delhi. All the consecutively reported AT cases were reviewed and reclassified as AT arising from sebaceous glands, hair follicles, or sweat glands. The concordance of clinical and histopathological diagnosis was also assessed.

Results:

Most of the ATs were benign (24/25) with head and neck being the most common location (72%). Nearly 56% of the tumors exhibited sweat gland differentiation, 28% hair follicle differentiation, and sebaceous gland tumors accounted for 16%. The most common varieties of tumors encountered in the present study included hidradenoma papilliferum and pilomatricoma. The concordance between clinical and histopathological diagnosis was found to be 50% approximately.

Conclusions:

ATs of the skin are rare neoplasms with benign tumors being far more common. They are often misdiagnosed clinically, so histopathology remains the gold standard for establishing an accurate diagnosis of skin ATs.

What is new in adnexal tumors of the skin?

This article reviews the recent dermatopathology literature regarding cutaneous adnexal neoplasms, with emphasis on new and underrecognized entities, "old entities" with new findings, advances in immunohistochemistry, and new findings in relation to inherited disorders associated with cutaneous adnexal neoplasms.