Penile intraepithelial neoplasia
Penile intraepithelial neoplasia, abbreviated PeIN, is the precursor of squamous cell carcinoma of the penis.
| Penile intraepithelial neoplasia | |
|---|---|
| Diagnosis in short | |
 Penile intraepithelial neoplasia (undifferentiated subtype). H&E stain. | |
| Subtypes | differentiated PeIN, undifferentiated PeIN |
| LM DDx | squamous cell carcinoma of the penis, squamous hyperplasia |
| IHC | p16 +ve (uPeIN) -ve (dPeIN), p53 -ve (uPeIN) +ve (dPeIN) |
| Site | penectomy grossing |
|
| |
| Associated Dx | HPV infection (undifferentiated PeIN), lichen sclerosus or BXO (differentiated PeIN) |
| Prevalence | uncommon |
| Prognosis | good |
| Clin. DDx | squamous cell carcinoma of the penis, lichen sclerosis, phimosis |
It may be abbreviated PIN;[1] however, this can cause confusion with the prostatic intraepithelial neoplasia (the presursor of prostate carcinoma).
General
- Not very common overall.
- Typically seen adjacent to squamous cell carcinoma of the penis.
Microscopic
Subclassified as:[2]
- Undifferentiated PeIN (uPeIN).
- Differentiated PeIN (dPeIN).
Note:
- Subclassification similar to one for vulvar intraepithelial neoplasia, that is based on the role of HPV in the pathogenesis.
Undifferentiated penile intraepithelial neoplasia
Features:
- Increased NC ratio.
- Multinucleation.
- Lack of maturation to surface - not that useful.
- May have "vertical streaming" - the long axis of the cells are perpendicular to the free surface & basement membrane.
- Apical mitoses.
DDx:
Differentiated penile intraepithelial neoplasia
Features:
- Thickening of the stratum spinosum (acanthosis).
- Elongation of rete ridges with bridging/anastomoses between rete ridges.
- Nuclear atypia - esp. of the basal layer.
- Nuclei in stratum corneum (parakeratosis).
- +/-Atypical mitoses.
DDx:
Images
uPeIN - low mag. (WC)
uPeIN - low mag. (WC)
uPeIN - intermed. mag. (WC)
uPeIN - intermed. mag. (WC)
uPeIN - high mag. (WC)
uPeIN - high mag. (WC)
Parakeratosis & reactive changes - intermed. mag. (WC)
IHC
- p16 -ve in dPeIN,[3] +ve in uPeIN.
See also
References
- ↑ Porter, WM.; Francis, N.; Hawkins, D.; Dinneen, M.; Bunker, CB. (Dec 2002). "Penile intraepithelial neoplasia: clinical spectrum and treatment of 35 cases.". Br J Dermatol 147 (6): 1159-65. PMID 12452865.
- ↑ Velazquez, EF.; Chaux, A.; Cubilla, AL. (May 2012). "Histologic classification of penile intraepithelial neoplasia.". Semin Diagn Pathol 29 (2): 96-102. PMID 22641959.
- ↑ Oertell, J.; Caballero, C.; Iglesias, M.; Chaux, A.; Amat, L.; Ayala, E.; Rodríguez, I.; Velázquez, EF. et al. (May 2011). "Differentiated precursor lesions and low-grade variants of squamous cell carcinomas are frequent findings in foreskins of patients from a region of high penile cancer incidence.". Histopathology 58 (6): 925-33. doi:10.1111/j.1365-2559.2011.03816.x. PMID 21585428.