Localized Bilateral Superior and Inferior Orbital Neurofibroma in the Absence of Neurofibromatosis

Table 1

Pathologic and immunophenotypic features useful in the differential diagnosis of Schwann cell neoplasms [15].

	Neurofibroma	Schwannoma	MPNST
Cytology
Nuclear size	+	++	++/+++
Nuclear hyperchromasia	+	++	+++
Wavy nuclei	+++	+	++
Histology
“Shredded carrot” type collagen	+++	−	−/+
Capsule	−	+++	−
Hyalinized vessels	−/+	+++	−
Fascicular growth pattern	−/+	++	+++
Mitotic activity	−/+	−/+	+++
Necrosis	−	−/+	+++
Immunohistochemistry marker
S100 protein	++/+++	+++	+/++
Collagen IV	++/+++	+++	+/++
EMA	+	−(capsular)	−
CD34	+++	+++	++
Neurofilament protein	++	+(capsular rare intratumoral axons)	+/+++
Podoplanin	+	++	+
Calretinin	+	+++	NA
Sox10	+++	+++	+/++

MPNST: malignant peripheral nerve sheath tumor; EMA: epithelial membrane antigen; NA: not applicable.