Atypical Presentation of Pilar Cyst Over the Volar Aspect of the Thumb: A Case Report and Review of Literature

Pilar cysts are derived from the outer layer of the root sheath of hair follicles. They were conventionally thought to arise from hair-bearing skin like the scalp. However, this notion has been refuted recently. Pilar cysts of the hand are extremely rare, with only a few case reports in the literature. We report the case of a 40-year-old male patient, with no known medical co-morbidities, who presented with a swelling over his left thumb. It was occasionally painful, and caused difficulty in grasping objects. Physical examination revealed a 2.5 x 1.5 cm swelling over the volar aspect of the thumb, at the level of the proximal phalanx. MRI revealed the presence of a well-defined cystic lesion superficial to the flexor tendons. The possibility of an epidermal cyst was considered, and the patient was advised surgery in view of his symptoms and progression in the size of the swelling. He underwent excision of the lesion along with a segment of adherent skin. Histopathological examination of the lesion revealed the presence of a pilar cyst. The patient did not have recurrence of symptoms following surgery, and was found to be doing well at the three-year follow-up. This case report urges a re-thinking of the possible origins of pilar cysts from atypical locations.

A solitary scalp mass as the presenting feature of clear cell sarcoma of the kidney in a pediatric patient

Clear cell sarcoma of the kidney is a rare renal malignancy, accounting for 2%-4% of all pediatric renal tumors. In this case report, we describe a 9-year-old boy with an asymptomatic, solitary mass on the scalp, ultimately found to be metastatic clear cell sarcoma of the kidney. This report reviews indications for imaging scalp masses to facilitate making an accurate diagnosis and treatment planning.

Removal of trichilemmal (pilar) cyst of the upper lip with intraoral approach in an adolescent patient

Trichilemmal cysts mainly occur in areas of dense hair follicle concentration. Locations include face, trunk, extremities and genitalia are less common. Prevalence and description of cases in the literature are rare in pediatric age. We report a pilar cyst removal from the upper lip with intraoral approach in an adolescent.

Pilar Cyst From a Maxillofacial Surgeon's Perspective: A Case Report and Review of Literature

Pilar cysts/trichilemmal cysts are benign lesions that arise from the hair follicle epithelium. The commonest area of occurrence is the scalp but it can also occur in the head and neck region. The pilar cyst grows at a prolonged rate. They are relatively rare and occur in about 10% of the population. They appear in the region of high concentrations of hair follicles. A 75-year-old male patient came to the Department of Oral and Maxillofacial Surgery with a chief complaint of swelling on the left side of the face for the past one year. Cytological examination revealed an infected cystic lesion. Computed tomography (CT) showed a well-defined lesion in the left temporal region. After surgical excision of the lesion, it was sent for histopathological examination. Excisional biopsy revealed a pilar cyst. We report a rare case of pilar cyst in the left temporal region in a patient who was previously operated on for osteomyelitis of the left side of the mandible up to the coronoid process. These cysts may mimic temporal space infection and lead to an incorrect treatment plan.

Distinguishing a Trichilemmal Cyst From a Pilomatricoma With Ultrasound

OBJECTIVES

To determine whether ultrasound (US) could distinguish a trichilemmal cyst from a pilomatricoma preoperatively.

METHODS

Ultrasound images of 61 pathologically proven trichilemmal cysts and 90 pathologically proven pilomatricomas were analyzed retrospectively. Two radiologists evaluated several US features. The sensitivity, specificity, Youden index, and predictive values of statistically significant US features were assessed. Parallel combined tests, serial combined tests, or both were performed to identify US features with high statistical significance.

RESULTS

Results from individual US features were not satisfactory; however, serial combined tests that included absence of complete internal echogenic foci, absence of a hypoechoic rim, absence of peritumoral hyperechogenicity, and absence of vascularity showed higher diagnostic utility. The sensitivity, specificity, Youden index, positive predictive value, and negative predictive value for correctly identifying a trichilemmal cyst were 74%, 88%, 0.62, 80%, and 83%, respectively. If 1 of these 4 US features was not a match for a trichilemmal cyst, pilomatricoma was considered.

CONCLUSIONS

It may be possible to distinguish trichilemmal cysts from pilomatricomas preoperatively using US. A combined test is superior to using any individual US feature.

Pilar cyst on the dorsum of hand: A case report and review of literature

RATIONALE

Pilar cyst mainly occurs on the scalp, but pilar cyst on the dorsum of hand has not been reported. Herein, we provide information to improve the clinical cognition of pilar cyst location.

PATIENTS CONCERNS

A 76-year-old man presented with a round nodule on the opisthenar of his right hand for two months without any subjective symptoms.

DIAGNOSES

Histological features of the lesion biopsy indicated the diagnosis of pilar cyst.

INTERVENTIONS

Surgical resection was made under local anesthesia.

OUTCOMES

Complete recovery was achieved after surgery.

CONCLUSION

Pilar cyst rarely occurs on the dorsum of hand and its diagnosis depends on histopathological examinations. Surgical resection is the only way to treat it.

Verrucous pilar cysts infected with beta human papillomavirus

Epidermoid cysts with histopathologic features of human papillomavirus (HPV) infection have been previously reported and are commonly termed verrucous cysts. We report a series of eight histopathologically distinct verrucous pilar cysts, distinguished from traditional verrucous epidermoid cysts by trichilemmal keratinization, as well as two verrucous hybrid pilar-epidermoid cysts. These lesions contain characteristic stratified epithelial linings with abrupt transitions to compact eosinophilic keratin, as well as areas of papillomatosis, coarse intracytoplasmic keratohyalin granules, and vacuolar structures suggestive of HPV-induced cytopathic change. HPV-24, a β genus HPV species, was identified by degenerate polymerase chain reaction in DNA extracted from two of the lesions, and the presence of β-HPV E4 protein was confirmed by immunohistochemistry. HPV-60, the HPV species most commonly reported in verrucous epidermoid cysts, was not detected. Verrucous pilar cysts represent histopathologically and potentially etiologically distinct lesions which may be underrecognized.

Case Report: A rapidly growing cyst on the scalp

Trichilemmal carcinoma is a rare tumour derived from the outer root sheath of hair follicles ^.  It can be difficult to distinguish both clinically and histologically from other skin lesions, particularly squamous cell carcinoma.  We present the case of a 62-year-old female with a 20-year history of three 1-cm cysts on her scalp.  Over a six-month period, a cyst overlying the occiput had become painful and grown in size.  The general practitioner and subsequently local emergency department suspected infection.  The lesion was incised, and the patient was treated with oral antibiotics.  At the time of surgical excision, the lesion measured 3 x 4 cm.

Microscopic examination identified rounded dermal lobules of squamous epithelium with trichilemmal keratinization, in keeping with a pre-existing pilar cyst.  There were areas with nuclear pleomorphism, mitoses and an infiltrative architecture.  A diagnosis of trichilemmal carcinoma arising in a pilar cyst was made.  Trichilemmal carcinomas are considered to be a low-grade tumour, but they have the potential to spread to lymph nodes and to metastasise to distant sites in the body, therefore adequate excision and appropriate follow-up are required.

Multiple Giant Pilar Cyst Distributed Over the Body Since Childhood

Trichilemmal cyst or pilar cyst is defined as a cyst containing keratin and its breakdown products. It is usually situated on the scalp with a wall resembling external hair root sheath. In this case report we present a 55-year-old man with multiple giant pilar cysts that were distributed over the whole body since childhood. One of the cyst on the chest was transformed to squamous cell carcinoma (SCC).