*Corresponding author email: dimmonteiro@gmail.com Symbiosis Group Symbiosis www.symbiosisonline.org www.symbiosisonlinepublishing.com Proliferating Trichilemmal Tumor - A Very Rare Disease In Young Adults Diana Monteiro 1 *, Jorge Pinheiro 2 , Pedro Silva 1 , Álvaro Silva 1 1 Department of Plastic, Reconstructive and Aesthetic and Burn Unity, Faculty of Medicine of Porto University, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal 2 Department of Pathology, Centro Hospitalar São João, Faculty of Medicine of Porto University, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal SOJ Surgery Open Access Letter to Editor Hematoxylin-eosin stain revealed a multilobular and cystic tumor with pushing borders and lobulated contour, occupying the dermis, involving the epidermis and opening into skin surface (Figure 2A). Lobules displayed peripheral palisading of small basaloid cells, differentiating towards large keratinocytes with ample eosinophilic cytoplasm and abrupt keratinization without a granular layer - trichilemmal keratinization (Figure 2B). Tumor cells showed moderate nuclear atypia, nuclear pleomorphism and scarce mitoses (Figure 2C). This was consistent with PTT, Abstract Proliferating Trichilemmal Tumor (PTT) is a very rare usually benign tumor found in the scalp and face of elderly females. However, at times, the tumor has aggressive clinical course and a propensity for nodal and distant metastases. We report cases of PTT over the scalp on a very uncommon age. Keywords: Cysts; Scalp neoplasms; Pilar tumor; Trichilemmal tumor; Trichilemmal keratinization Received: 09 August, 2016; Accepted: 16 August, 2016; Published: 26 August, 2016 *Corresponding author: Diana Isabel Moreira Monteiro, Department of Plastic, Reconstructive and Aesthetic and Burn Unity, Faculty of Medicine of Porto University, Alameda Professor Hernâni Monteiro, Rua da Rasa, no 119, 4º Esquerdo, 4400-271 Vila Nova Gaia, Portugal, Tel: +351.93.8232590; E-mail: dimmonteiro@gmail.com Trichilemmal Tumor (PTT), first recognized by Wilson-Jones 1966 [1] is a rare, usually benign tumor of Proliferating external root sheath derivation affecting scalp, eyelids, neck and face of elderly female patients. It have been reported with varying nomenclature, e.g., invasive pilomatrixioma, proliferating epidermoid cyst, trichoclamydocarcinoma and pilar tumor [1-2] It is a slow growing, large, solitary, multilobulated lesion that may arise within a pilar cyst. These tumors are largely benign, often cystic, and are characterized by trichilemmal keratinization. Tumors with an invasive growth pattern or cytologic atypia have an unpredictable course and may be locally aggressive or have a propensity for nodal and distant metastases. Thus, it has been suggested that even the classical PTT should be considered as carcinoma [2-3]. Due to its rarity, there are no guidelines available for the management of these tumors. A 30-year-old woman (patient 1) and a 26-year-old pregnant woman (patient 2) presented with a swelling on the parietal and occipital region of the scalp, with diameters of 3 and 2.5cm, respectively. The lesions had evidently been growing in the last 3 months. There was no pain or erythematic or history of trauma or lymadenopathy in both patients. Their medical history was unremarkable. The nodular masses with a smooth surface and soft consistency, were not fixed to the underlying skull bone and periosteum. There were no palpable adenomegalies. Total lesion surgical excision with a 0.5 cm margin of normal tissue was performed under local anesthesia (Figure 1). Figure 1: Asymptomatic nodule on the sclap (patient 2) Figure 2a: Multlobular and cystc tumor (patent 1 H&E, x 4)