Vet’s 2025 Guide to Hair Follicle Tumors & Cysts in Dogs – Types, Diagnosis & Care 🐶

By Dr. Duncan Houston BVSc

💡 What Are Hair Follicle Tumors?

Hair follicle tumors are growths originating from the components of the skin’s hair-making unit. In dogs, they account for around 10% of skin tumors—most are benign, though rare malignant forms exist.

🌀 Common Types

• Trichoblastoma: Most common benign tumor of hair matrix cells (root); typically solitary and seen in breeds like Poodles and Cocker Spaniels.
• Infundibular Keratinizing Acanthoma (IKA): Occurs in follicle upper part; may discharge keratin and pus; often on trunk or neck.
• Trichoepithelioma: Benign, often multiple small facial/trunk lumps filled with cheesy material; may recur after excision.
• Pilomatricoma: Root-origin tumor; usually benign but rare malignant forms exist.
• Cysts: Follicular cysts are benign, fluid- or keratin-filled; can become infected; often surgically removed.

📌 Signs to Spot

• Firm, slow-growing lumps on the skin surface; may ulcerate or ooze if IKA or cyst
• Sometimes itchy, crusted, secondarily infected
• Malignant tumors are rare; signs include rapid growth, invasiveness, and ulceration 

🧪 Diagnosing Tumor Types

• Physical exam: size, shape, discharge, ulceration
• Fine-needle aspirate or biopsy: differentiates tumor types and benign vs malignant status
• Histopathology confirms the diagnosis; understanding follicular anatomy helps classify tumors accurately 

✂️ Treatment Options

• Surgical removal: Preferred, especially for solitary or symptomatic tumors; often curative for benign types
• Monitoring: Small, non-irritating cysts or epitheliomas can be observed unless they grow or become inflamed
• Antibiotics: If cysts or tumors become infected
• Advanced therapy: Rare malignant cases may benefit from radiation, chemotherapy, or targeted agents

📈 Prognosis & Follow-Up

• Benign tumors like trichoblastomas and IKAs have excellent outcomes post-removal.
• Trichoepitheliomas may recur at new sites; regular physical exams help early detection
• Malignant hair follicle tumors are rare but require vigilant follow-up

🛡️ Preventive Care

• Breed predisposition: monitor breeds like Standard Poodle, Cocker Spaniel, and Schnauzer
• Check skin monthly for new nodules; note changes in existing bumps
• Prompt vet evaluation of unusual or growing lumps

📲 Owner Tools & Support

• Ask A Vet: Telehealth helps in interpreting biopsies and managing skin lumps

🌟 Case Snapshot

Case: Rosie, a 6-year-old Cocker Spaniel, had a slow-growing round lump by her shoulder. Biopsy confirmed trichoblastoma. Surgical removal led to full healing, and six-month skin checks have stayed clear ever since. 🐾

✅ Key Takeaways

• Most hair follicle tumors are benign and treatable
• Common types include trichoblastomas, IKAs, trichoepitheliomas, pilomatricomas & cysts
• Diagnosis requires biopsy/histopathology
• Surgical removal cures most; monitor for recurrence
• Early vet evaluation leads to the best skin health outcomes 🐕🩺

📥 Need Advice?

Have a new skin lump on your dog? Download the Ask A Vet app for real-time support with skin exams, biopsy interpretation, and care plans. Visit AskAVet.com to stay ahead of skin health. 🩺🐾