A comparative study of pilomatricoma and epidermoid cyst with ultrasound

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

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) cm3, and 81.3% of the patients' tumor volume ≤1.0 cm3. 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 (P1 = 3.10E-05 and P2 = 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 cm3. 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.

Ultrasonic liquid level detection method based on the variation of reflected energy on the inner wall of a container

Liquid level detection plays an important role in industry. For the liquid level detection of flammable, explosive and volatile liquids, the detection method based on the ultrasonic principle is usually adopted. Though a lot of efforts, the detection precision is still challenging. Herein, Ultrasonic liquid level detection method is studied to address the detection precision. A projection model of the inner wall of the sound beam is established. The transmitter-receiver probe is placed near the height of the liquid level on the outer wall of the liquid tank. The sound beam emitted by the probe passes through the tank wall and generates a projection area on its inner wall. The energy of the echo signal received by the probe is calculated, and the relationship between the proportion of liquid in the projection area and the energy is used to detect changes in the liquid level. The test system is set up, the echo signal received by the probe is collected, and its normalized energy is calculated. The results show that for different tank wall thicknesses, liquid types and detection frequencies, the normalized energy can clearly characterize the change of liquid level with an error of less than 3 mm. It provides a new avenue for liquid level detection. The research also shows that for the determined detection frequency, when the tank wall thickness corresponds to the values greater than or equal to the critical distance of the probe, the detection accuracy of liquid level change is the highest.

Ultrasound features of benign paediatric lumps: radiology-pathology correlation

Ultrasonography is an appropriate first-line imaging technique for the characterisation of paediatric lumps, given its relative accessibility and absence of radiation exposure. Together with a thorough history and examination, ultrasonography can help to distinguish benign lesions from malignancy. It can also aid further characterisation of benign lesions to inform onward investigation and management. This review features the evaluation of common benign paediatric lumps together with their characteristic sonographic features, following correlation with histopathology results or clinical follow-up.

Pilomatricoma: Clinical, Dermoscopic Findings and Management in 55 Pediatric Patients and Concise Review of the Literature with Special Emphasis on Dermoscopy

INTRODUCTION

Pilomatricoma is a benign adnexal dermal or subcutaneous tumor derived from immature hair matrix cells.

OBJECTIVES

The aim of our study is to evaluate clinical and dermoscopic features of pilomatricomas, with a specific focus on pediatric lesions, and to provide a concise review of the existing literature.

METHODS

A single-center retrospective study was undertaken on 55 patients with a histopathological diagnosis of pilomatricoma referred to the Dermatology Unit, University of Bologna, Bologna, Italy, between 2005 and 2023. Pilomatricomas were retrospectively evaluated relying on clinical and dermoscopic images. A PubMed search was conducted. All the relevant research up to July 31, 2023, was reviewed. We classified the cases as "typical" or "atypical" based on whether they were suspected of being pilomatricomas or not.

RESULTS

A total of 55 children with pilomatricomas were observed and studied. Two patients presented with 2 pilomatricomas, leading to the identification of 58 pilomatricomas. 'Typical' pilomatricomas were observed in 79% of cases as nodular and pigmented lesions with one or more colors, ranging from blue-gray to red to yellow/white, evident on clinical examination and even better on dermoscopy. In 21% of cases, pilomatricomas presented in an 'atypical' form, which did not allow for a well-founded suspicion, placing them in differential diagnosis with other lesions and therefore requiring histological examination.

CONCLUSIONS

According to our case series and systematic review of the literature, clinical appearance and dermoscopy may be sufficient to diagnose or suspect pilomatricoma in around 80% of cases, while histological examination is necessary to confirm the diagnosis in the remaining 20% of cases.

Integrating vascularity into the pattern classification of pilomatricomas on ultrasound provides a more competent approach for discriminative evaluation

BACKGROUND

Pilomatricoma has various manifestations on color Doppler ultrasound, and a differential diagnosis is challenging. The objective of this study was to investigate which characteristics of skin lesions on color Doppler ultrasound are effective in distinguishing pilomatricoma from epidermoid cyst and dermatofibrosarcoma protuberans.

MATERIALS AND METHODS

Records of patients with pilomatricomas (n = 63), epidermoid cysts (n = 76), and dermatofibrosarcoma protuberans (n = 19) who underwent color Doppler ultrasound evaluation and surgical excision were reviewed. The anatomical distribution and color Doppler ultrasound characteristics of these lesions were analyzed. The 63 pilomatricomas were categorized into five types based on their color Doppler ultrasound characteristics, and the roles of these five types in the differential diagnosis of the aforementioned diseases were studied.

RESULTS

Pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans exhibited some similar characteristics. Dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity were the major characteristics of pilomatricomas. The pilomatricomas could be categorized into five types, with type II having a diagnostic performance of sensitivity of 65.08%, specificity of 98.95%, area under the receiver operating characteristic curve (AUC) of 0.743, positive predictive value of 97.62%, and negative predictive value of 81.03% for the diagnosis of the aforementioned skin diseases.

CONCLUSION

A combination of dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity exhibits higher diagnostic performance for the differential diagnosis of pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans.