Cutaneous scalp metastases from breast carcinoma (CMBC) represent an uncommon manifestation of metastatic disease, with heterogeneous clinical presentations, including nodular or infiltrative lesions and scarring alopecia (alopecia neoplastica). The absence of standardized diagnostic criteria, particularly for alopecic phenotypes, poses challenges to early recognition of CMBC, which may represent either the first indication of neoplastic progression or a late recurrence. We retrospectively analyzed a multicenter cohort of 15 patients with histologically confirmed CMBC. Demographic, clinical, molecular, and trichoscopic data were collected and correlated with the main clinical phenotypes: patchy alopecia (alopecia neoplastica) versus nodules/plaques. The statistical analyses we performed were the Mann-Whitney test for group comparisons and Fisher's exact test for categorical variables. The median age at CMBC diagnosis was 64 years. Alopecia neoplastica was the most frequent phenotype (53.3%). Patients with alopecia neoplastica showed a longer median interval between primary tumor diagnosis and metastasis onset compared to those with nodules/plaques (73.5 months vs. 59.5 months; p = 0.11). Trichoscopic analysis revealed significant differences in the distribution of features between the alopecia neoplastica group and the nodular/plaque group. Statistically significant differences were found among the two groups, including linear-irregular vessels (87.5% vs. 28.6%, p = 0.041), polymorphic vessels (87.5% vs. 28.6%, p = 0.041), pili torti (75% vs. 14.3%, p = 0.041), follicular hyperkeratosis and follicular plugging (87.5% vs. 14.3%, p = 0.01). Overall, the trichoscopic pattern in alopecia neoplastica appeared more variable and heterogeneous compared to that observed in the nodular/plaque phenotype. Alopecia neoplastica, often underestimated in clinical practice, emerges as the predominant CMBC phenotype in our cohort and is associated with a distinct trichoscopic profile. The complexity of the alopecic phenotype may reflect intrinsic biological differences compared to nodular lesions. Larger prospective studies are needed to validate these findings and incorporate trichoscopic profiles into standard diagnostic pathways.

The BCS1L gene encodes a mitochondrial chaperone which inserts the Fe2S2 iron-sulfur Rieske protein into the nascent electron transfer complex III. Variants in the BCS1L gene are associated with a spectrum of mitochondrial disorders, ranging from mild to severe phenotypes. Björnstad syndrome, a milder condition, is characterized by sensorineural hearing loss (SNHL) and pili torti. More severe disorders include Complex III Deficiency, which leads to neuromuscular and metabolic dysfunctions with multi-systemic issues and Growth Retardation, Aminoaciduria, Cholestasis, Iron Overload, and Lactic Acidosis syndrome (GRACILE). The severity of these conditions varies depending on the specific BCS1L mutation and its impact on mitochondrial function. This study describes a 27-month-old child with SNHL, proximal renal tubular acidosis, woolly hypopigmented hair, developmental delay, and metabolic alterations. Genetic analysis revealed a homozygous BCS1L variant (c.38A>G, p.Asn13Ser), previously reported in a patient with a more severe phenotype that, however, was not functionally characterized. In this work, functional studies in a yeast model and patient-derived fibroblasts demonstrated that the variant impairs mitochondrial respiration, complex III activity (CIII), and also alters mitochondrial morphology in affected fibroblasts. Interestingly, we unveil a new possible mechanism of pathogenicity for BCS1L mutant protein. Since the interaction between BCS1L and CIII is increased, this suggests the formation of a BCS1L-containing nonfunctional preCIII unable to load RISP protein and complete CIII assembly. These findings support the pathogenicity of the BCS1L c.38A>G variant, suggesting altered interaction between the mutant BCS1L and CIII.

Lichen planopilaris (LPP) is a well-known cicatricial alopecia with a frontal fibrosing variant. LPP has a prevalence rate of 13.4 per 100,000 persons. It is understood that LPP favors the female populations. What is not commonly known is that LPP can be preceded by other signs and symptoms such as pili torti. We present a case report of a 70-year-old female whose initial flare of LPP was preceded by a flare of pili torti. This patient's case is also complicated by her history of ectodermal dysplasia. She experienced progressive itching, shedding, and mid-scalp hair loss along with brittle curls which failed to improve with intralesional steroids and minoxidil, which prompted further investigation. This case highlights how early intervention and detection can allow for treatment and prevention of further hair loss in patients with LPP and as well as other alopecias. Treatment of patients at onset of disease is crucial to prevent permanent hair loss.

Polarized transilluminating dermoscopy is a novel technique that can be used to diagnose hair shaft disorders. The technique has been used once to describe the findings of trichothiodystrophy, but its use in other hair shaft disorders has not yet been studied. To assess the efficacy and utility of polarized transilluminating dermoscopy (PTD) in various hair shaft disorders and describe the observations noted. Six patients with suspected hair shaft disorder were enrolled based on history and clinical examination. Trichogram, trichoscopy, and PTD were performed in all the cases, and the findings were described. PTD enhances the visualization of hair shaft disorders, including pili torti, trichorrhexis nodosa, trichorrhexis invaginata, pili trianguli et canaliculi, and woolly hair. The utilization of the given method in hair analysis represents a significant advancement in the field, offering distinctive insights into the inner structures of hair shafts. In contrast to simple trichoscopy using a polarizing dermatoscope, PTD revealed detailed defects and was confirmatory for the diagnosis of the respective disorder.

Marie-Unna hereditary hypotrichosis (MUHH) is an autosomal dominant disorder characterized by a specific pattern of hair loss. Initially described in 1925 by Marie-Unna in a German family spanning over seven generations, MUHH represents a previously unidentified form of congenital hypotrichosis. It typically presents as sparse hair at birth with a coarse texture, followed by regrowth during childhood then, finally, gradual hair loss at puberty, resembling pattern of androgenetic alopecia. The study describes two cases from different unrelated families presenting with recalcitrant alopecia resembling female pattern hair loss, with dermoscopic findings consistent with pili torti and yellow dots. Genetic testing confirmed a heterozygous pathogenic variant in the HRURF gene, associated with autosomal dominant Marie Unna Hereditary Hypotrichosis. Up to our knowledge it is first case series reported from Egypt. While recent literature on MUHH has primarily focused on identifying genetic abnormalities, there are other important questions that warrant consideration. These include histopathological studies, dermoscopic descriptions, and correlating types of genetic mutations with clinical presentations. These data might offer a deeper understanding of MUHH pathophysiology ending in efficacious treatment options. Marie-Unna hereditary hypotrichosis (MUHH) is a rare genetic condition that causes a distinct pattern of hair loss. First identified in 1925 in Germany, this condition is passed down through families. In this article, we report two unrelated cases from Egypt, marking the first documented cases of MUHH in the country. Each case involves different genetic mutations, highlighting the variability of the condition. MUHH typically presents as sparse hair at birth, which becomes coarse in childhood and then gradually thins again during puberty. This hair loss can resemble common male-pattern baldness. While MUHH mainly affects hair, it may also be linked to other conditions such as skin tumors (trichoepithelioma), limb abnormalities, eye issues, wide-spaced teeth, and syndromes like Ehlers-Danlos or atopy. Because MUHH is so rare, diagnosing it can be difficult, and many healthcare providers may not immediately recognize it. By describing these cases, we aim to raise awareness and improve understanding of MUHH, encouraging clinicians to consider it as a possible diagnosis in similar presentations.