Proliferating Pilar Tumors: Can Immunohistochemistry Differentiate Benign and Malignant Forms?

The Programmed Cell Death Ligand 1 and Lipocalin 2 Expressions in Primary Breast Cancer and Their Associations with Molecular Subtypes and Prognostic Factors

Purpose

Breast cancers exhibit molecular heterogeneity, leading to diverse clinical outcomes and therapeutic responses. Immune checkpoint inhibitors targeting PD-L1 have shown promise in various malignancies, including breast cancer. Lipocalin 2 (LCN2) has also been associated with tumor aggressiveness and prognostic potential in breast cancers. However, the expression of PD-L1 and LCN2 in breast cancer subtypes and their prognostic implications remains poorly investigated.

Methods

A retrospective analysis of 89 primary breast cancer cases was conducted to assess PD-L1 and LCN2 expressions using immunohistochemistry. Cases were classified into four different molecular subtypes based on ER, PR, HER2, and Ki-67 status. Associations between PD-L1 and LCN2 expressions and various prognostic factors were examined.

Results

Although low expression of LCN2 (Allred score of <3) was observed even in normal breast tissue, LCN2 expression with increasing Allred score (≥3) positively correlated with the histological grade, high Ki-67 proliferation index, and ER/PR negativity. Significant elevations of LCN2 and PD-L1 expressions were observed in triple-negative and HER2-positive breast cancers.

Conclusion

The results of the study highlight the association of LCN2 with known prognostic factors and molecular subtypes. To identify potential immunotherapy recipients, it would be useful to evaluate LCN2 as well as PD-L1 immune targets in different subgroups of breast cancer patients. Further studies with larger patient numbers are warranted to validate these observations and establish standardized scoring criteria for LCN2 expression assessment.

Proliferating Pilar Tumors in the Scalp Over a Period of 23 Years in a General Hospital in Mexico City

BACKGROUND

Proliferating pilar tumors are an unusual skin tumor, and they have a cystic component with trichilemmal keratinization and epithelial proliferation. These arise from the outer root sheath of hair follicles. It mainly affects women. The scalp is the most affected area. Diagnosis can be made by biopsy. Surgical excision is the best treatment option.

OBJECTIVE

Report the frequency of proliferating pilar tumors in the scalp in general hospital in Mexico over a period of 23 years.

METHODS

The authors reviewed the database of the dermatopathology service of the General Hospital "Dr Manuel Gea González" from 1999 to August 2022, selecting diagnosticated cases of proliferating pilar tumor, pilar cyst, trichilemmal cyst, or proliferating trichilemmal cyst in the scalp.

RESULTS

The authors discovered 17 cases, 13 were women, the average age was 54.9 years, all the tumors affecting the scalp, and just 3 cases were reported as malignant.

CONCLUSION

In comparison with the existing data, the authors can observe that most of their patients were women and the scalp is the most affected area. Most did not present associated symptoms. As the authors can see, most are benign and long-lasting: however, the authors cannot ignore that a small percentage can be malignant.

Proliferating Pilar Tumors Are Characterized by Recurrent 15q, 6q, and 6p22.2 Alterations

ABSTRACT

Proliferating pilar tumors (PPTs) are rare neoplasms of external root sheath derivation, which most commonly occur on the scalp of elderly women. Although typically showing classic histologic features such as trichilemmal type keratinization, a lobular architecture and peripheral palisading, squamous cell carcinoma (SCC) remains a common diagnostic pitfall. Therefore, we sought to explore the molecular pathogenesis of PPTs and compare it with that of cutaneous squamous cell carcinoma (cSCC). Herein, we describe the use of a next-generation DNA sequencing platform to provide the most comprehensive molecular genetic analysis to date of a cohort of 5 PPTs and compare them to 5 head and neck cutaneous SCCs. Recurrent broad arm-level gains of 15q and concurrent single-copy losses of 6q and 6p22.2 were observed in 4 of 5 (80%) PPT cases. Other recurrent mutations or alterations of significance were not found in PPTs. Notably, these chromosomal changes were not identified in any of the 5 cutaneous SCCs, which instead showed recurrent alterations in the known SCC driver genes TP53 , CDKN2A , and NOTCH1 . Here, we show for the first time that PPTs are molecularly distinct from cutaneous SCC and provide evidence that recurrent alterations in chromosome 15 and chromosome 6 are central to the pathogenesis of PPTs.