Melanocytic matricoma is a rare benign pilar tumor characterized by matrical differentiation and interspersed dendritic melanocytes. It may show cellular atypia and brisk mitotic activity. Histological characterization of some lesions may be difficult. In addition, because the reported cases are few and have limited follow-up, there is insufficient experience to define outcome-based criteria for malignancy. Some cases of melanocytic matricoma with more prominent atypia have been reported as malignant, but their clinical behavior is uncertain. We present a melanocytic matricoma with interspersed benign dendritic melanocytes, but moderate basaloid atypia, focally brisk mitotic activity, and atypical mitoses. Despite the apparently good delimitation of this tumor, higher magnification revealed a slightly irregular border. However, overt malignant features such as necrosis, frank asymmetry, deep infiltration, and ulceration were not present. This tumor showed a complex aberrant genomic profile with multiple whole chromosomes or chromosomal arms, losses, and duplications. The tumor mutational burden was high. A loss-of-function alteration in CDKN2A and a loss-of-function mutation in TP53 were also present. This unexpected molecular profile contrasts with the relatively bland histology of the tumor and is in line with the difficulties in microscopic differential diagnosis between melanocytic matricoma and an indolent malignant pilomatrical tumor. We suggest that molecular studies and longer follow-up periods may help to further understand and more precisely categorize borderline pilomatrical tumors with melanocytic hyperplasia.

This thesis investigated the efficacy and safety of a new autologous breast reconstruction technique: autologous fat transfer (AFT). A randomized controlled trial compared AFT to the current standard therapy with breast implants. Results showed AFT can be used on its own to create voluminous breasts and women who underwent AFT had a higher quality of life following breast reconstruction. Furthermore, AFT is safe, cost-effective and results in a higher sensibility of the breasts while not affecting the donor sites. Results of this thesis led to AFT for total breast reconstruction being added to the list of reimbursed treatments in the Netherlands. This is encouraging news for post-mastectomy breast cancer women searching for a third breast reconstruction option.

Breast implant surgery is one of the most commonly performed procedures by plastic surgeons worldwide. Breast implants are used for both cosmetic breast augmentation and breast reconstruction. Questions about the safety of silicone breast implants have existed since they were first used. Some women report general physical complaints, such as fatigue, muscle pain, joint pain and cognitive complaints, which they relate to the implants. This pattern of complaints, also known as breast implant illness (BII), has received considerable media attention. This dissertation aimed to provide scientific evidence surrounding this topic so that plastic surgeons can provide their patients with appropriate information. Several studies examined how often these physical complaints occur in women with breast implants, what factors influence the development of these complaints and what the effect of removing the implants is. Furthermore, the complaints and quality of life in women with breast reconstruction were investigated.

The number of transgender adolescents seeking gender-affirming surgery (GAS) in increasing. Surgical care of the adolescent transgender patient is associated with several unique technical, legal, and ethical factors. The authors present a review of the current literature on gender-affirming surgery for individuals under the age of legal majority and propose directions for future research. A scoping review of recent literature was performed to assess evidence on gender-affirming surgery in individuals under the age of legal majority. Articles were included that examined either ethical or technical factors unique to pediatric GAS. Study characteristics and conclusions were analyzed in conjunction with expert opinion. Twelve articles were identified that met inclusion criteria. Ten of these articles discussed ethical challenges in adolescent GAS, seven discussed legal challenges, and five discussed technical challenges. Ethical discussions focused on the principles of beneficence, nonmaleficence, and autonomy. Legal discussions centered on informed consent and insurance coverage. Technical discussions focused on the effects of puberty blockade on natal tissue. Surgical care of the adolescent transgender patient involves important ethical, legal, and technical considerations that must be addressed by the clinical team. As the population of individuals seeking GAS after puberty blockade increases, future research is needed describing functional and psychosocial outcomes in these individuals.