Clinical overview
"Vulvar epithelial hyperplasia" is an old clinico-pathological label that the FCOG(SA) registrar must handle carefully, because the term has been retired, redefined and partly re-absorbed into other entities over the last three decades. In the historical (pre-2004) ISSVD scheme, the chronic white vulvar plaques were lumped together as "vulvar dystrophies" and split into hyperplastic dystrophy (now called squamous cell hyperplasia), lichen sclerosus, and mixed dystrophy. "Squamous cell hyperplasia" was the diagnosis given to a thickened, hyperkeratotic vulvar epithelium showing acanthosis and hyperkeratosis but no atypia and no identifiable dermatosis — in practice, the histological footprint of chronic rubbing and scratching, i.e. lichen simplex chronicus. The clinical complaint is almost always vulvar pruritus with a palpable, leathery, white or grey thickened plaque, and the central clinical anxiety is whether this lesion is a benign reactive change, a precursor of squamous carcinoma, or an already-malignant lesion masquerading as a benign one.
The reason this objective is weighted as higher-order thinking (HOTS) rather than rote recall is that the registrar must integrate terminology (old "hyperplasia" vs current WHO-2020 categories), the two divergent pathways to vulvar squamous carcinoma (HPV-associated vs HPV-independent), and a low threshold for biopsy in a South African population with high HIV prevalence and therefore high HPV-driven disease burden. Getting the pathology right drives the entire management chain: reassurance and topical steroid for benign hyperplasia, versus excision and oncological work-up for differentiated VIN or invasive cancer. Distinguishing these on a small white plaque is genuinely difficult, which is precisely why histology — not clinical inspection — is the arbiter. Cross-reference the precursor and invasive ends of this spectrum at Lichen sclerosus and Vulval carcinoma.
Core knowledge
Terminology: what "epithelial hyperplasia" means now
The single most important exam point is that the WHO Classification of Tumours of the Female Genital Tract, 5th ed (2020) no longer recognises "vulvar dystrophy" or "hyperplastic dystrophy" as diagnoses. The vulvar epithelial disorders are now sorted into:
- Non-neoplastic / inflammatory dermatoses — lichen sclerosus, lichen planus, and lichen simplex chronicus (the lesion the old term "squamous cell hyperplasia" mostly described). These show no epithelial atypia.
- Squamous intraepithelial neoplasia — divided by aetiology:
- HPV-associated (usual-type) VIN, graded in WHO-2020/LAST terminology as LSIL (flat condyloma / VIN 1 equivalent) and HSIL (VIN 2–3 / usual-type VIN equivalent).
- HPV-independent VIN, of which differentiated VIN (dVIN) is the prototype, plus the newer entities differentiated exophytic vulvar intraepithelial lesion (DEVIL) and vulvar acanthosis with altered differentiation (VAAD).
- Invasive squamous cell carcinoma and its variants.
So when a referral says "squamous cell hyperplasia" or "vulvar epithelial hyperplasia", the registrar's job is to decide which modern bucket the biopsy actually belongs in. The crucial intellectual move is recognising that acanthosis (epithelial thickening) is the shared morphological theme across benign lichen simplex chronicus, the reactive epithelium adjacent to lichen sclerosus, and the deceptively bland-looking dVIN. The presence or absence of atypia, and where that atypia sits in the epithelium, is what separates benign from premalignant.
Gross / macroscopic features
Benign vulvar squamous (epithelial) hyperplasia — lichen simplex chronicus — presents as a localised, well-demarcated, raised, leathery plaque, usually on the labia majora, mons, or lateral labia. The surface is often white (a clinically "leukoplakic" plaque from hyperkeratosis and surface maceration), sometimes grey or dull pink, with accentuated skin markings (lichenification) and excoriation marks from scratching. It is typically firm and thickened to palpation but not indurated in the way an invasive cancer is, and there is no ulceration, no fixed nodularity and no friable bleeding surface — those features mandate biopsy to exclude malignancy. Lesions may be solitary or multiple and are frequently symmetrical when the underlying driver is generalised itch.
The diagnostic difficulty is that all of these macroscopic descriptors overlap with early dVIN and with HPV-associated HSIL, and with lichen sclerosus (which is classically porcelain-white, atrophic, "cigarette-paper" wrinkled, with loss of architecture, agglutination of the labia minora and clitoral burying). Mixed pictures are common: lichen sclerosus and squamous hyperplasia frequently coexist, and that combination historically carried the highest malignant-transformation worry.