Figure 1. Conventional cNF. (A) The lesion is made of scattered spindle cells that correspond to Schwann cells, fibroblasts and mast cells admixed numerous capillaries (Hematoxylin & eosin (H&E) stain, 50×) (B) (H&E, 100×). (C) Lesional cells surrounding the pilosebaceous unit (H&E, 40×).

Figure 1. Conventional cNF. (A) The lesion is made of scattered spindle cells that correspond to Schwann cells, fibroblasts and mast cells admixed numerous capillaries (Hematoxylin & eosin (H&E) stain, 50×) (B) (H&E, 100×). (C) Lesional cells surrounding the pilosebaceous unit (H&E, 40×).

Figure 2. Clear/Balloon cell cNF (A) Collection of large clear vacuolated cells, H&E, 200× (courtesy: Dr. Tamie Ferringer) (B) Cells with from clear to granular cytoplasm, round nuclei and prominent nucleoli, H&E, 400× (courtesy: Dr. Wilsher).

Figure 2. Clear/Balloon cell cNF (A) Collection of large clear vacuolated cells, H&E, 200× (courtesy: Dr. Tamie Ferringer) (B) Cells with from clear to granular cytoplasm, round nuclei and prominent nucleoli, H&E, 400× (courtesy: Dr. Wilsher).

Figure 3. Dendritic cell cNF with pseudorosettes: pseudorosettes with type I cells concentrically surrounding type II cells H&E, 100×.

Figure 3. Dendritic cell cNF with pseudorosettes: pseudorosettes with type I cells concentrically surrounding type II cells H&E, 100×.

Figure 4. cNF showing wreath like multinucleated giant cells, H&E, (400×) (courtesy: Dr. Lynne Goldberg).

Figure 4. cNF showing wreath like multinucleated giant cells, H&E, (400×) (courtesy: Dr. Lynne Goldberg).

Figure 5. Pacinian cNF, clusters of spherical bodies resembling rudimentary Pacinian corpuscles are embedded in mature adipose tissue, H&E, 10× (courtesy: Dr. Raj Singh, www.PathPresenter.net accessed on 1 October 2022). Figure 5. Pacinian cNF, clusters of spherical bodies resembling rudimentary Pacinian corpuscles are embedded in mature adipose tissue, H&E, 10× (courtesy: Dr. Raj Singh, www.PathPresenter.net accessed on 1 October 2022).

Figure 6. Pigmented cNF (A) Haphazardly arranged oval to spindle cells containing dark crown pigment, H&E, 100×; (B) positive for Mart-1, (immunohistochemical stain, 200×).

Figure 6. Pigmented cNF (A) Haphazardly arranged oval to spindle cells containing dark crown pigment, H&E, 100×; (B) positive for Mart-1, (immunohistochemical stain, 200×).

Figure 7. Atypical cNF (A) Banal and atypical cells are seemingly haphazardly arranged in a collagenous stroma, H&E, 100× (B) The atypical cells have hyperchromatic irregular nuclei. H&E, 200× (courtesy: Dr Raj Singh, www.PathPresenter.net accessed on 1 October 2022). Figure 7. Atypical cNF (A) Banal and atypical cells are seemingly haphazardly arranged in a collagenous stroma, H&E, 100× (B) The atypical cells have hyperchromatic irregular nuclei. H&E, 200× (courtesy: Dr Raj Singh, www.PathPresenter.net accessed on 1 October 2022).

Figure 8. Large cystic spaces containing mucinous materials without any epithelial lining in a cystic NF (A) H&E, 20×, (B) H&E, 200×.

Figure 8. Large cystic spaces containing mucinous materials without any epithelial lining in a cystic NF (A) H&E, 20×, (B) H&E, 200×.

Figure 9. Myxoid cNF, neoplastic spindle cells in abundant mucinous matrix H&E 100×.

Figure 9. Myxoid cNF, neoplastic spindle cells in abundant mucinous matrix H&E 100×.

Figure 10. Sclerotic cNF, spindle-shaped cells with wavy cytoplasm and elongated nuclei embedded in markedly dense sclerotic stroma, H&E, 20×.

Figure 10. Sclerotic cNF, spindle-shaped cells with wavy cytoplasm and elongated nuclei embedded in markedly dense sclerotic stroma, H&E, 20×.

Figure 11. Lipomatous cNF, lesion showing interlacing fascicles or whorls of spindle cells focally intermingled with adipose tissue., H&E, 20×.

Figure 11. Lipomatous cNF, lesion showing interlacing fascicles or whorls of spindle cells focally intermingled with adipose tissue., H&E, 20×.

Figure 12. Angioneurofibroma, H&E, 100× (courtesy: Dr. Kaya Gürkan).

Figure 12. Angioneurofibroma, H&E, 100× (courtesy: Dr. Kaya Gürkan).

Figure 13. Plaque like NF in the upper dermis, H&E, (A) 02×, (B) 05X, (C)-MART-1, 02x. (courtesy: Deon Wolpowitz).

Figure 13. Plaque like NF in the upper dermis, H&E, (A) 02×, (B) 05X, (C)-MART-1, 02x. (courtesy: Deon Wolpowitz).

Figure 14. Ill-defined lesion composed of haphazardly arranged spindle cells in between collagen bundles, H&E, 20×.

Figure 14. Ill-defined lesion composed of haphazardly arranged spindle cells in between collagen bundles, H&E, 20×.

Table 1. Classification of neurofibroma.

Table 1. Classification of neurofibroma.

Anatomic locationCutaneous
Cutaneous/subcutaneous
DeepGrowth PatternLocalized
Diffuse/infiltratingRelationship to nerveIntraneural
ExtraneuralPathogenesisEndoneurial
Perineurial
Epineurial

Table 2. Histopathological variants of Cutaneous Neurofibroma.

Table 2. Histopathological variants of Cutaneous Neurofibroma.

Conventional/Classic cNFAccording to variations in cell morphology:

Epithelioid;

Granular cell;

Balloon cell/clear cell;

Dendritic cell NF with pseudorosettes;

Floret-like multinucleated giant cells;

Meissnerian;

Pacinian;

Pigmented/melanotic;

Atypical;

Cellular;

Microcystic pseudoglandular.

According to the variations in stroma:

Myxoid;

Hyalinized;

Sclerotic;

Lipomatous;

Angioneurofibroma.