From: Oral carcinoma cuniculatum: an unacquainted entity with diagnostic challenges—a case report
OCC | VC | PSCC | Well-differentiated OSCC | |
---|---|---|---|---|
Histologic features | ||||
Epithelium | Well-differentiated squamous epithelium | Well-differentiated squamous epithelium | Keratinizing type: dysplastic squamous epithelium non-keratinizing type: immature cells | Well-differentiated squamous epithelium |
Cellular atypia | Absent or minimal (bland squamous cells) | Absent or minimal (bland squamous cells) | Severe (dysplastic squamous cells or immature basaloid cells) | Severe (dysplastic squamous cells) |
Basement membrane | Invasive disruption of the basement membrane | Intact basement membrane with lateral spread | Invasive disruption of the basement membrane | Invasive disruption of the basement membrane |
Growth pattern | Endophytic ± exophytic growth pattern predominantly endophytic growth, however both endophytic and exophytic growth can occur | Exophytic and endophytic growth pattern | Exophytic and endophytic growth pattern | Variable exophytic and/or endophytic growth pattern |
Exophytic component | The surface is usually smooth but maybe exophytic. When exists the surface has a blunt pebbly ‘cobble stone’ appearance | Typically, the warty verrucous pattern with surface has vertical pointed ‘church spire-like’ fronds that show excessive surface keratin, clefting, and parakeratin plugging | The surface has a papillary ‘filiform’ pattern with thin central cores covered by malignant epithelial cells with minimal or no keratinization | When exists the surface has an irregular, fungating, papillary, or verruciform appearance |
Endophytic component | Endophytic multiple deep burrowing ‘rabbit burrow’ or ‘cuniculi’ pattern of a complex arborizing network of invasive tumor cells with keratin-filled crypts and tortuous cystic structures into connective tissue is the hallmark of this lesion | The proliferating epithelium shows deeply invasive ‘pushing’ front of broad blunt elongated rete ridges and restricted to the lamina propria | The endophytic squamous proliferation of tumor cells into connective tissue | The endophytic squamous proliferation of tumor cells into connective tissue |
Infiltrating tumor islands | No infiltrating tumor islands | Infiltrating tumor islands | Infiltrating tumor islands | |
Invasion/infiltration | Locally destructive, infiltrative tumor | Superficial invasion | Locally destructive, infiltrative tumor | Aggressive locally destructive, infiltrative tumor |
Keratin | Network of keratin-filled burrows and crypts in the connective tissue | Marked surface keratinization, so-called ‘church-spire keratosis’ | Variable amount mostly confined to the surface | Abundant |
± Keratin pearls | Parakeratosis and parakeratin plugging | ± Keratin pearls | ++ Keratin pearls | |
Metastasis | Rare | Non-metastasizing | Uncommon | Frequent/early |
Recurrence | Rare | Can recur | Can recur | Can recur |
Prognosis | Worse prognosis than VC, but better prognosis than both PSCC and conventional OSCC | Better prognosis than OCC, PSCC, and conventional OSCC | Better prognosis than conventional OSCC | Worse prognosis than VC, OCC, and PSCC (According to clinical TNMa staging) |
Therapy | Wide surgical excision for cases with no bone invasion Subtotal maxillectomy or mandibulectomy with a safety margin for cases associated with bone invasion ± neck dissection in extensive cases | Wide surgical excision | Wide surgical excision + chemo- and/or radiotherapy | Stage I and II tumors are treated with en bloc resection ± neck dissection Stage III and IV tumors are treated with surgery with neck dissection + chemo- and/or radiotherapy |