Isolated pilomatricoma of the arm: A case and a review of the literature

Pilomatricoma is a relatively rare tumor of the skin derived from primitive basal cells of the epidermis that differentiate into hair matrix cells. These tumors appear as solitary, firm nodules, showing a normal to pearl white epidermis. Its most frequent locations are the head and neck, while involvement of the upper extremities is relatively uncommon. Herein, we present the case of a seventeen-year-old female with pilomatricoma of the arm and review the literature regarding pilomatricomas of the upper extremities. The diagnosis of pilomatricoma is confirmed histologically and its treatment is based on surgical excision. Because of the low incidence and variable clinical presentation, pilomatricoma is a tumor not commonly suspected preoperatively. This presentation may help clinicians to diagnose this entity more effectively and decrease the rate of misdiagnosis.

Temporal evolution of human mercury exposure in the Amazon

Due to the current global attention to mercury exposure and toxicity, as well as its various consequences on ecosystems and human health, new scientometric tools help to better understand the issues involved. In this literature research, studies of the risk of human exposure to mercury in populations of the Brazilian Amazon biome in the last three decades were contemplated using scientometric techniques, bibliographic docking, authors, citations, and keywords. The analyses of the period from 1991 to 2019 enabled the selection of 130 articles. There was the identification of the main research institutions, classification and interrelations of the main thematic axes of the studies in the Amazon biome and most cited authors. The most referenced articles on this theme and the main bioindicators were ordered. The results show that most of the studies were carried out along rivers and with riverside populations. In the sample universe, there is a predominance of localities on the Tapajós and Madeira Rivers. Most researchers work only with internal partnerships, without interaction with other scientific groups. The hair matrix is the main bioindicator of Hg exposure used by the authors. For future perspective, this paper has the potential to represent a general temporal understanding of human exposure to mercury in the Amazon and its main bioindicators.

128 Rapidly Proliferative Pilomatrixoma On the Eyebrow of A 7-Year-Old Boy – A Case Report

Pilomatrixoma or calcifying epithelioma of Malherbe is a benign tumour originating from pluripotent precursors of hair matrix cells. We present a paediatric patient with a rapidly enlarging eyebrow mass with a differential diagnosis of sebaceous cyst, pyogenic granuloma, or malignancy. A 7-year-old boy presented in primary care with a 0.5cm non-inflammatory nodule on his medial brow present for 2-3 months. History of previous trauma was not elicited and there were no features of bleeding or ulceration. It was then lanced, following diagnosis of an infected sebaceous cyst. Within weeks, the nodule underwent rapid proliferation, enlarging to 2cm in diameter. He was urgently referred to secondary care pending further investigation for possible trauma-induced pyogenic granuloma or malignancy. Upon presentation in secondary care, we observed a protruding erythematous and ulcerated mass, indurated in texture and adherent to overlying skin. The patient was submitted to excisional biopsy with a vertical elliptical approach to minimise distortion of the brow. Small, calcified deposits were observed in the tumour substance. Histologically, basaloid basophilic cells were predominant and mixed with ghost cells and foci of giant multinucleate cells, verifying diagnosis of a pilomatrixoma. Pilomatrixoma exhibits tendency towards mimicry of lesions such as epidermoid, sebaceous, dermoid cyst, pyogenic granuloma or even keratoacanthoma with a pre-operative detection rate as low as 11%. With a bimodal age distribution, arising in the first and sixth decades of life, this case highlights a need for a high degree of suspicion in young patients with careful clinical examination in order to aid diagnosis and prompt appropriate treatment.

Hair Analysis to Evaluate Polydrug Use

Polydrug use is a frequent pattern of consumption in Europe. This behavior has mainly been analyzed within restricted groups; more rarely in large populations. Current polydrug use is less studied than simultaneous use. This study focused on the concurrent assumption of polydrug among drivers using hair matrix. Hair matrix, for its biological characteristics, allows to identify illicit drug use more often than other matrices, i.e., urine, and it provides information on the long-term use of them. Hair samples of subjects positive for opiates, cocaine and delta-9-tetrahydrocannabinol (Δ9-THC) collected by the forensic toxicology laboratory of the University of Macerata in the period 2010–2020, were analyzed using a gas chromatography-mass spectrometry method. Our results evidenced that a significant part of the examined population (12.15%) used polydrug. A strong predominance of males over females was evident. Polydrug users were more frequently young people. The abuse of two substances was predominant. Cocaine and Δ9-THC was the most common combination, followed by cocaine and morphine, and morphine and Δ9-THC. The timeframe of polydrug use was also analyzed. Our study shows that polydrug use is a very frequent behavior, and that hair analysis may be a powerful tool to obtain objective biological information of this complex phenomenon.

Identification of 2C-B in Hair by UHPLC-HRMS/MS. A Real Forensic Case

The analysis of drugs of abuse in hair and other biological matrices of forensic interest requires great selectivity and sensitivity. This has been traditionally achieved through target analysis, using one or more analytical methods that include different preanalytical stages, and more complex procedures followed by toxicological laboratories. There is no exception with 2C-series drugs, such as 2C-B, a new psychoactive substance (NPS), which use has emerged and significantly increased, year by year, in the last decades. Continuously new analytical methods are required to selectively detect and identify these new marketed substances at very low concentrations. In this case report, one former case of a polydrug consumer (charged of a crime against public health in Spain) was reanalyzed in hair matrix. In this reanalysis, 2C-B has been positively detected and identified using liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS/MS). The most selective analytical UHPLC-HRMS/MS method alongside a universal and simpler pretreatment methodology has opened up more possibilities for the detection of substances of different chemical structure and optimization of different HRMS/MS detection approaches allowing the identification of 2-CB in the hair of a real forensic case.

Does endometrial morular metaplasia represent odontogenic differentiation?

The nature of endometrial morular metaplasia (MorM) is still unknown. The nuclear β-catenin accumulation and the not rare ghost cell keratinization suggest a similarity with hard keratin-producing odontogenic and hair matrix tumors rather than with squamous differentiation. We aimed to compare MorM to hard keratin-producing tumors. Forty-one hard keratin-producing tumors, including 26 hair matrix tumors (20 pilomatrixomas and 6 pilomatrix carcinomas) and 15 odontogenic tumors (adamantinomatous craniopharyngiomas), were compared to 15 endometrioid carcinomas with MorM with or without squamous/keratinizing features. Immunohistochemistry for β-catenin, CD10, CDX2, ki67, p63, CK5/6, CK7, CK8/18, CK19, and pan-hard keratin was performed; 10 cases of endometrioid carcinomas with conventional squamous differentiation were used as controls. In adamantinomatous craniopharyngiomas, the β-catenin-accumulating cell clusters (whorl-like structures) were morphologically similar to MorM (round syncytial aggregates of bland cells with round-to-spindled nuclei and profuse cytoplasm), with overlapping squamous/keratinizing features (clear cells with prominent membrane, rounded squamous formations, ghost cells). Both MorM and whorl-like structures consistently showed positivity for CD10 and CDX2, with low ki67; cytokeratins pattern was also overlapping, although more variable. Hard keratin was focally/multifocally positive in 8 MorM cases and focally in one conventional squamous differentiation case. Hair matrix tumors showed no morphological or immunophenotypical overlap with MorM. MorM shows wide morphological and immunophenotypical overlap with the whorl-like structures of adamantinomatous craniopharyngiomas, which are analogous to enamel knots of tooth development. This suggests that MorM might be an aberrant mimic of odontogenic differentiation.

Pilomatrixoma with Atypical Features: A Case Report

Pilomatrixoma is an uncommon, benign tumor with differentiation towards both the hair matrix and cells arising in the cortex, most frequently appearing in the first or second decade of life. In rare instances, pilomatrixomas can show malignant transformation. Pilomatrix carcinoma is extremely uncommon and has traditionally been considered a tumor of low malignant potential; however, a high local recurrence rate has been reported. There is a paucity of literature on these lesions, with only a few reports describing the spectrum of malignant changes seen in these lesions. In this case report, we present a case of pilomatrixoma in an adult patient showing atypical features. While the tumor is small, there are focal features that suggest progression to malignancy, but do not fulfill the criteria for pilomatrix carcinoma. These focal atypical features include a focal infiltrative pattern at the periphery, with a variable cytological atypia and an increased mitotic rate, up to five mitotic events/high-power field. Irregular foci of central necrosis (comedonecrosis) were present in several lobules. Some of the features identified were similar to a subset of pilomatrixoma, known as “proliferating pilomatrixoma.” However, our case did not have the diffuse changes or larger size that has been frequently reported in “proliferating pilomatrixoma.” In conclusion, given the lack of focality of the changes, the lesion in our case is best described as a pilomatricoma with atypical features. Furthermore, our case may highlight the need to ensure close clinical follow-up for these lesions with unexpected atypical features that raise concern of recurrence and malignant transformation.

Towards developing an organotypic model for the preclinical study and manipulation of human hair matrix-dermal papilla interactions

Organ culture of microdissected scalp hair follicles (HFs) has become the gold standard for human ex vivo hair research; however, availability is becoming very limited. Although various simplistic “HF-equivalent” in vitro models have been developed to overcome this limitation, they often fail to sufficiently mimic the complex cell–cell and cell–matrix interactions between epithelial and mesenchymal cell populations that underlie the specific growth processes occurring in a native HF. Here, we have attempted to overcome these limitations by developing a novel human hair research model that combines dermal papilla (DP) fibroblasts, cultured as 3-dimensional (3D) spheroids (DPS), with plucked anagen hair shafts (HS). We show that DPS express HF inductivity markers, such as alkaline phosphatase (ALP), versican and noggin, while plucked HSs retain substantial remnants of the anagen hair matrix. When cultured together, DPS adhere to and surround the plucked HS (HS-DPS), and significantly enhance HS expression of the differentiation marker keratin-85 (K85; p < 0.0001), while simultaneously decreasing the percentage of TUNEL + cells in the proximal HS (p = 0.0508). This simple model may offer a physiologically relevant first step toward evaluating HF differentiation in the human anagen hair matrix.

An isolated pilomatricoma of the leg: a rare location – A Case Study

Pilomatricoma is a rare, benign skin tumour arising from the hair matrix. The usual locations are the head and neck. Localization in the lower limbs is exceptional. The diagnosis of certainty is histological. Treatment is complete surgical removal to avoid recurrence. We report in this article the case of a rare localization of a pilomatricoma on the right leg, in a 25-year-old patient operated with complete surgical removal. The postoperative course was simple and without recurrence after 2 months of follow-up.

miR-140-5p in Small Extracellular Vesicles From Human Papilla Cells Stimulates Hair Growth by Promoting Proliferation of Outer Root Sheath and Hair Matrix Cells

The application of dermal papilla cells to hair follicle (HF) regeneration has attracted a great deal of attention. However, cultured dermal papilla cells (DPCs) tend to lose their capacity to induce hair growth during passage, restricting their usefulness. Accumulating evidence indicates that DPCs regulate HF growth mainly through their unique paracrine properties, raising the possibility of therapies based on extracellular vesicles (EVs). In this study, we explored the effects of EVs from high- and low-passage human scalp follicle dermal papilla cells (DP-EVs) on activation of hair growth, and investigated the underlying mechanism. DP-EVs were isolated by ultracentrifugation and cultured with human scalp follicles, hair matrix cells (MxCs), and outer root sheath cells (ORSCs), and we found low-passage DP-EVs accelerated HF elongation and cell proliferation activation. High-throughput miRNA sequencing and bioinformatics analysis identified 100 miRNAs that were differentially expressed between low- (P3) and high- (P8) passage DP-EVs. GO and KEGG pathway analysis of 1803 overlapping target genes revealed significant enrichment in the BMP/TGF-β signaling pathways. BMP2 was identified as a hub of the overlapping genes. miR-140-5p, which was highly enriched in low-passage DP-EVs, was identified as a potential regulator of BMP2. Direct repression of BMP2 by miR-140-5p was confirmed by dual-luciferase reporter assay. Moreover, overexpression and inhibition of miR-140-5p in DP-EVs suppressed and increased expression of BMP signaling components, respectively, indicating that this miRNA plays a critical role in hair growth and cell proliferation. DP-EVs transport miR-140-5p from DPCs to epithelial cells, where it downregulates BMP2. Therefore, DPC-derived vesicular miR-140-5p represents a therapeutic target for alopecia.