Proliferating trichilemmal cyst

Alternate names

Proliferating pilar cyst

Definition

Proliferating trichilemmal tumor (PTT) is a benign tumor originating from the hair follicle. Although it is a benign tumor, PTT may be locally aggressive and in very rare cases the tumor may become malignant.

Signs and symptoms

• In most cases there is only one lesion and occur in elderly women.
• The tumor is not painful but sometimes they may grow very large and pressure and damage the skin around it resulting in wounds and foul-smelling discharge. About 90% of the cases are on the scalp, but they have also been found on the forehead, nose, back, chest, abdomen, buttocks, elbow, wrist and genitalia.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Epidermoid cyst(Skin cyst)
• Skin ulcer(Open skin sore)

30%-79% of people have these symptoms

• Sparse scalp hair(Reduced/lack of hair on scalp)

Diagnosis

• The diagnosis of MPTC is essentially based on histological features.
• The presence of a high mitotic rate, atypical mitosis, severe nuclear pleomorphism, and tumor invasion of the adjacent tissues are the essential histological features of malignancy in these unusual tumors.

Treatment

Treatment is with surgery removing the lesion.

Prognosis

Prognosis is good in most cases but the patient should be followed closely after surgery.

External links

Classification	ICD-10: L72.1
External resources	Orphanet: 492