Cylindroma
Cylindroma (cutaneous cylindroma) is a rare benign adnexal tumor that arises from epithelial stem cells differentiating toward sweat gland ducts (mainly eccrine/apocrine) or the folliculo-sebaceous-apocrine unit. It is made up of islands of basaloid cells packed tightly together in a jigsaw-puzzle mosaic, each surrounded by a thick hyaline basement membrane.
CYLD Mutations and the NF-κB Signaling Pathway
- The CYLD gene (16q12.1): CYLD encodes a deubiquitinating enzyme that removes Lys63-linked ubiquitin chains from signaling proteins such as TRAF2, TRAF6 and NEMO/IKK-γ.
- How growth control is lost: A loss-of-function mutation in CYLD weakens the brake on NF-κB signaling. NF-κB stays switched on, sending anti-apoptotic signals that drive unchecked proliferation of basaloid cells in the dermis.
Sporadic vs. Familial Forms (Brooke-Spiegler Syndrome)
- Sporadic cylindroma: Caused by a somatic CYLD mutation; usually a single nodule on the face or scalp in an adult.
- Familial form (familial cylindromatosis/Brooke-Spiegler syndrome, BSS): Caused by an autosomal dominant germline CYLD mutation. Dozens to hundreds of tumors develop on the scalp and can merge into a large mass covering the whole scalp, known as a "turban tumor." These often occur alongside spiradenomas and trichoepitheliomas.
Because cylindromas extend deep into the dermis and subcutis, treatment at Haute-Derma is tailored to each patient:
- Accurate microscopic diagnosis: High-frequency (20–50 MHz) skin ultrasound combined with biopsy and immunohistochemistry (IHC) confirms the tumor is benign and maps its relationship to the fascia and periosteum.
- Microsurgical or Mohs excision: The whole tumor is removed with clear margins while minimizing injury to nerve branches and scalp muscle, preserving the appearance of the scalp and face.
Histopathology, Immunohistochemistry (IHC) and Imaging Criteria
Cylindroma has a classic histology that is easy to recognize under the light microscope thanks to its distinctive architecture:
- Jigsaw-puzzle (mosaic) pattern: Tumor lobules and basaloid nests sit right next to each other, molded against one another like puzzle pieces, with no fibrous stroma between neighboring islands.
- Thick eosinophilic hyaline sheath: Each island is wrapped in a thick, uniform basement-membrane sheath that stains strongly pink with eosin and is PAS-positive and diastase-resistant (PAS+D+).
- Dual cell population:
- Peripheral cells: Small cells with dark nuclei arranged in a palisade at the edge of each island (germinative cells).
- Central cells: Larger cells with pale nuclei and ample cytoplasm in the middle of each island (ductal differentiation).
- Intralobular hyaline droplets: Eosinophilic hyaline droplets are scattered within the tumor islands.
Differential IHC Marker Panel
| IHC marker / stain | Where it is expressed in the tumor | Histologic significance |
|---|---|---|
| PAS (periodic acid–Schiff) + diastase | Sheath around tumor islands and intralobular droplets | Strongly positive (++); confirms the hyaline basement membrane |
| p63 / CK5/6 | Small peripheral cells of the islands | Strongly positive (++); confirms basaloid germinative cells |
| CK7 / EMA / CEA | Central cells and small duct lumens | Focally positive (+); confirms ductal differentiation |
| CD34 | Connective-tissue stroma around the tumor | Positive in thin stromal bands; helps distinguish from basal cell carcinoma |
| Ki-67 index | All tumor cells | Very low (<5%) in benign tumors; >30% in malignant cylindrocarcinoma |
High-Frequency Ultrasound and Dermoscopy Criteria
- High-frequency skin ultrasound:
- Lesion appearance: A well-defined, clearly lobulated hypoechoic mass in the dermis and subcutis.
- Capsule: A thin hyperechoic rim around the lobules, corresponding to the thick hyaline sheath.
- Color Doppler: Moderate vascularity concentrated in the connective tissue around the lobules.
- Dermoscopy:
- Background: Structureless areas that are pale pink, brick red or skin-colored.
- Vessels: Clearly branching arborizing vessels over a smooth, shiny surface, which can easily be mistaken for basal cell carcinoma (BCC).
Clinical Features
- Typical lesion: A firm, smooth, hairless, round papule or nodule, pale pink to deep red or slightly purple, from 0.5 cm to several centimeters across.
- Preferred sites: Very common on the scalp (>90%) and face; rare on the trunk.
- Warning signs of malignant change (cylindrocarcinoma): Sudden rapid growth, surface ulceration, bleeding, persistent pain, and fixation to the underlying skull.
Treatment at Haute-Derma
At Haute-Derma, cylindroma management follows a strictly standardized protocol designed to remove the tumor at its root, prevent recurrence and achieve the best possible appearance of the scalp and face:
Deep Imaging and Antibody-Based Biopsy
- Ultrasound mapping: Measures how deep the tumor lobules extend relative to the skull periosteum so that surgery can be planned safely.
- Biopsy with IHC typing: A panel of PAS, p63, CK7 and Ki-67 index rules out morpheaform basal cell carcinoma and cylindrocarcinoma. Patients with multiple tumors are offered CYLD genetic screening.
Specialized Treatment
Fractional Er:YAG 2940 nm laser micro-ablation:
- Used for small cylindromas (<5 mm) located in the superficial dermis.
- The 2940 nm Er:YAG beam vaporizes each tumor lobule precisely at micrometer resolution, removing the tumor base without harming nearby hair follicles.
Complete microsurgical excision / Mohs micrographic surgery:
- Used for large tumors (>1 cm), tumors in cosmetically sensitive areas of the face, or turban tumors.
- The tumor is excised with a 2–3 mm margin. The entire deep and peripheral margin is examined on frozen sections on site, and the wound is closed only once the margins are confirmed free of tumor (clear margins).
Biological Recovery and Multilayer Cosmetic Closure
- Biological layer of exosomes plus Pincer biomodulation: Right after excision, purified stem-cell exosomes and Pincer biomodulation are applied to the defect to promote healthy new blood vessels and speed healing of the wound bed.
- Three-layer subcuticular closure: The wound is closed with fine 7-0 cosmetic sutures, with the edges brought snugly together along natural skin lines so the scar is well hidden at the hairline or in natural creases.
- Vbeam 595 nm laser: Treatment 10–14 days after surgery closes off new post-operative blood vessels and helps prevent red or hypertrophic scars.
