Figure 4From: Microfollicular adenoma of ectopic thyroid gland masquerading as salivary gland tumor – a diagnostic and therapeutic challenge: a case report Composite photomicrograph. (a) Cytoplasmic and membrane positivity for cytokeratin 7 immunostain (400×); (b) negativity for cytokeratin 20 immunostain (400×); (c) nuclear positivity for retinoblastoma immunostain (400×); and (d) extracellular positivity for collagen type IV immunostain (400×).Back to article page