2025 ICD-10-CM code L72.12

Trichodermal cyst, also known as a trichilemmal (proliferating) cyst.

Use additional codes to specify any associated inflammation or infection.

Medical necessity for excision of a trichilemmal cyst is typically established by the presence of symptoms such as pain, discomfort, rapid growth, ulceration, or concern for malignancy.

Diagnosis and treatment of trichilemmal cysts is usually managed by dermatologists or general surgeons. Complete surgical excision is the recommended treatment for benign cysts to prevent recurrence. Malignant cysts may require more extensive treatment.

In simple words: A trichilemmal cyst is a type of skin cyst that originates from the outer root sheath of a hair follicle. It commonly appears on the scalp as a firm, dome-shaped lump.

A trichilemmal cyst is a benign neoplasm with tricholemmal differentiation. It is more common in women and typically presents as a solitary, multilobular, large, exophytic mass on the scalp. It can have benign or malignant characteristics, with benign cases typically having an indolent course and malignant cases potentially being locally aggressive, recurring, or metastasizing.

Example 1: A 45-year-old woman presents with a solitary, firm, dome-shaped nodule on her scalp. Upon examination, it is diagnosed as a trichilemmal cyst, and surgical excision is recommended., A 60-year-old man presents with a rapidly growing, ulcerated nodule on his scalp. Biopsy reveals a malignant trichilemmal cyst, requiring wider excision and potential adjuvant therapy., A 25-year-old woman has multiple small cysts on her scalp, consistent with trichilemmal cysts.She elects to have the largest, most symptomatic cyst excised.

Documentation should include the location, size, and characteristics of the cyst, as well as any associated symptoms.If excised, the pathology report should be documented.

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