Clinical and Pathological Features of Pilomatrixoma in Children: A Retrospective Study

Abstract

Introduction: Pilomatrixoma is a benign skin neoplasm that is common in children and is often misdiagnosed. This study aimed to summarize the clinical and pathological features of pilomatrixoma in children. Methods: Data on demographic information, clinical and pathological features, diagnosis, and treatment of 171 patients with pilomatrixoma from Shenzhen Baoan Women’s and Children’s Hospital were collected and analyzed retrospectively. Results: The mean age of the patients was 5.7 (standard deviation [SD] = 3.9) years old, and there were 2 age peaks (≤1 year old, 5–11 years old) and 2 age valleys (2–4 years old, ≥12 years old). The mean disease course was 9.3 (SD = 14.1) months, 69.0%, 86.5%, and 95.3% of the patients’ disease course in 6 months, 12 months, and 24 months, respectively. The mean tumor volume was 0.6 (SD = 1.0) cm ³, and 81.3% of the patients’ tumor volume ≤1.0 cm ³. Tumors were distributed sequentially in the head and neck (77.2%), upper limbs (12.9%), trunk (7.6%), and lower limbs (2.3%). The correct rates of clinical and ultrasonic diagnosis were 50.9% and 38.6%, respectively. The two most common pathological features of pilomatrixoma were shadow cells (99.4%) and basaloid cells (94.7%). There were no significant differences in age, disease course, or tumor volume between the male and female patients ( p > 0.05). The age and tumor volume of the patients in different body parts were significantly different ( P ₁ = 3.10E−05 and P ₂ = 5.60E−05, respectively). The correlation between the disease course and tumor volume was positively significant ( p ≤ 0.05). There was a significant correlation between the disease course and tumor volume in patients with tumors at upper limbs ( p = 0.03). Conclusion: The age of children with pilomatrixoma presented 2 peaks and 2 valleys. Most patients had disease courses in 24 months and with tumor volumes ≤1.0 cm ³. The correct rates of clinical and ultrasonic diagnosis were relatively low. The head and neck were the most common distribution sites of pilomatrixoma, and shadow cells and basaloid cells were the most common pathological features. The tumor volume was positively correlated with disease course in patients with pilomatrixoma.

Plain Language Summary

Pilomatrixoma is a benign skin neoplasm that is common in children and is often misdiagnosed. Fu et al. conducted a retrospective study at Shenzhen Baoan Women’s and Children’s Hospital. One hundred and seventy-one children with pilomatrixoma were included. There were 2 age peaks (≤1 year old, 5–11 years old) and 2 age valleys (2–4 years old, ≥12 years old). The mean disease course was 9.34 months, 69.0%, 86.5%, and 95.3% of the patients’ disease course in 6 months, 12 months, and 24 months, respectively. The mean tumor volume was 0.6 cm ³, and 81.3% of patients’ tumor volume ≤1 cm ³. Tumors were distributed sequentially in the head and neck (77.2%), upper limbs (12.9%), trunk (7.6%), and lower limbs (2.3%). The correct rates of clinical and ultrasonic diagnosis were 50.9% and 38.6%, respectively. The pathological features of pilomatrixoma were shadow cells (99.4%), basaloid cells (94.7%), calcification (39.8%), multinuclear giant cell aggregation (35.7%), inflammatory cell infiltration (33.9%), histiocytic hyperplasia (5.3%), and ossification (1.2%). There were no significant differences in age, disease course, or tumor volume between the male and female patients ( p > 0.05). The age and tumor volume of the patients in different body parts were significantly different ( P ₁ = 3.10E−05 and P ₂ = 5.60E−05, respectively). The correlation between the disease course and tumor volume was positively significant ( p ≤ 0.05). There was a significant correlation between the disease course and tumor volume in patients with tumors at upper limbs ( p = 0.03).