Diseases of the Penis

Overview

Covered by skin+foreskin(prepuce)+stratified squamous mucosa. Structure: 2 dorsal CORPORA CAVERNOSA + 1 ventral CORPUS SPONGIOSUM(urethra passes through, expanded end=GLANS). Urethral lining: prostatic part=transitional, most of course=columnar, near orifice=stratified squamous.

Developmental/inflammatory disorders

Glans+prepuce commonly inflamed — specific STIs: syphilitic hard chancre, chancroid(Haemophilus ducreyi), gonorrhoea, herpes progenitalis, granuloma inguinale(donovanosis), lymphogranuloma venereum(Chlamydia trachomatis).

PHIMOSIS — prepuce too small to retract. Congenital or acquired(inflammation/trauma/oedema). →↓cleanliness→secondary infection, preputial calculi, SCC (genuine cancer risk factor, not just mechanical nuisance). PARAPHIMOSIS — forcible retraction→constriction over glans+swelling.

HYPOSPADIAS/EPISPADIAS — hypospadias=meatus opens VENTRALLY(fails reaching tip); epispadias=DORSALLY. Both→urethral constriction+infection+ejaculation interference. Both linked to CRYPTORCHIDISM.

BALANOPOSTHITIS — non-specific prepuce(balanitis)+glans(posthitis) inflammation. Staph/strep/coliform/gonococci. Usually poor hygiene→secretion/smegma accumulation. Common with phimosis.

BALANITIS XEROTICA OBLITERANS — white atrophic glans/prepuce lesion = penile counterpart of vulval lichen sclerosus et atrophicus.

Tumours

Benign

CONDYLOMA ACUMINATUM(anogenital wart) — HPV types 6+11. Single/conglomerated papillomas. GIANT CONDYLOMA(Buschke-Löwenstein tumour/verrucous carcinoma)=extensive exophytic cauliflower variant.

Morphology: commonly coronal sulcus/perineum. Gross=warty cauliflower exophytic. Micro=resembles common warts(papillary villi, hyperkeratosis, parakeratosis, prickle cell hyperplasia); KOILOCYTOSIS(clear vacuolation)=HPV indicator. Giant condyloma=up+downward growth, histologically identical to condyloma BUT clinically INTERMEDIATE behaviour(recurs) between benign condyloma and SCC — histologic benignity ≠ predicting clinical course here.

Premalignant (carcinoma in situ, 3 lesions)

BOWEN’S DISEASE — penile shaft+scrotum(+sun-exposed skin). Gross=solitary circumscribed ulcerated plaque. Micro=superficial epidermal hyperplasia+hyperkeratosis+parakeratosis+bizarre dyskeratotic cells. ASSOCIATED with INTERNAL VISCERAL CANCERS in notable proportion (→ prompts systemic cancer screening).

ERYTHROPLASIA OF QUEYRAT — penile mucosa. Gross=pink shiny velvety-soft. Micro=thickened acanthotic epidermis+variable dysplasia. NO internal malignancy association (KEY CONTRAST with Bowen’s — compact tested pair, same premalignant behaviour but only one has systemic implication).

BOWENOID PAPULOSIS — penile shaft/genital skin. Gross=solitary/multiple shiny red-brown papules. Micro=orderly maturation+scattered hyperchromatic/dysplastic cells.

Malignant — Squamous cell carcinoma

Incidence varies widely: <1% of US male cancers, but 3-4x more in Black>White. Asian/African/Latin American countries: ~10% of all cancers. Strong HPV link(types 16+18, DNA in malignant nuclei). RARE in circumcised Jews/Muslims (India: rare in circumcised Muslims, higher in uncircumcised Hindus) — circumcision protects via preventing smegma accumulation(believed carcinogenic) — clear example of surgical/cultural practice altering cancer incidence via understood mechanism, parallels HPV-cervical cancer framework. Peak age 45-60.

Morphology: Gross=sites(↓freq) frenum>prepuce>glans>coronal sulcus; cauliflower/papillary or flat/ulcerating. Micro=well-mod differentiated, resembles SCC elsewhere. Spread: lymphatic→regional nodes; haematogenous=uncommon, advanced disease only.

Clinical relevance

Bowen’s vs erythroplasia of Queyrat = compact high-yield pair — nearly identical premalignant behaviour, but ONLY Bowen’s has internal visceral malignancy association → drives whether systemic cancer screening is pursued. Circumcision’s protective effect = clear surgical/cultural-practice→cancer-incidence case study (smegma mechanism), parallels HPV 16/18-cervical cancer framework. Giant condyloma’s intermediate clinical behaviour despite benign histology = reminder that histologic benignity doesn’t always predict clinical course. Phimosis = genuine SCC risk factor (impaired hygiene+chronic smegma), not just mechanical nuisance.

Overview

The penis is covered by skin, foreskin (prepuce), and stratified squamous mucosa. Structure: two dorsal corpora cavernosa plus one ventral corpus spongiosum (through which the urethra passes), the latter’s expanded free end forming the glans. Urethral lining varies: transitional epithelium in the prostatic part, columnar epithelium through most of its course, stratified squamous near the orifice.

Developmental and Inflammatory Disorders

Glans and prepuce are frequently involved in inflammation — specific infections include sexually transmitted diseases (syphilitic hard chancre, chancroid from Haemophilus ducreyi, gonorrhoea, herpes progenitalis, granuloma inguinale/donovanosis, lymphogranuloma venereum from Chlamydia trachomatis).

Phimosis — the prepuce is too small to retract normally behind the glans; congenital (developmental) or acquired (from inflammation, trauma, or oedema narrowing the preputial opening). Interferes with cleanliness, predisposing to secondary infection, preputial calculi, and squamous cell carcinoma. Paraphimosis — forcible retraction of a phimotic prepuce, constricting over the glans and causing swelling.

Hypospadias/epispadias — developmental urethral defects: hypospadias = meatus opens on the ventral surface (fails to reach the tip); epispadias = meatus opens dorsally. Both may cause urethral constriction with secondary infection and interfere with ejaculation/insemination; both are more frequently associated with cryptorchidism.

Balanoposthitis — non-specific inflammation of the prepuce’s inner surface (balanitis) plus adjacent glans surface (posthitis), from staphylococci, streptococci, coliform bacilli, gonococci; usually from poor cleanliness causing secretion/smegma accumulation; commonly accompanies phimosis; acute or chronic, sometimes with glans mucosal ulceration.

Balanitis xerotica obliterans — a white atrophic glans/prepuce lesion, the penile counterpart of vulval lichen sclerosus et atrophicus.

Tumours

Benign Tumours

Condyloma acuminatum (anogenital wart) — benign, from HPV types 6 and 11; single or conglomerated papillomas. A more extensive, exophytic, solitary, cauliflower-like variant is the giant condyloma (Buschke-Löwenstein tumour, verrucous carcinoma).

Morphology: commonly on the coronal sulcus or perineum. Gross — solitary/multiple warty cauliflower-shaped exophytic lesions. Micro — resembles common warts: papillary villi (connective tissue stroma covered by squamous epithelium showing hyperkeratosis, parakeratosis, prickle-cell-layer hyperplasia); many prickle cells show koilocytosis (clear cytoplasmic vacuolation, indicating HPV infection). Giant condyloma shows both upward and downward growth but is otherwise histologically identical — though histologically benign, it clinically recurs and behaves as an intermediate entity between true benign condyloma and squamous cell carcinoma.

Premalignant Lesions (Carcinoma in Situ)

Three lesions on external male genitalia show malignant cytologic change confined to the epithelium without invasion:

Bowen’s disease — located on the penile shaft and scrotum (also sun-exposed skin elsewhere). Gross: solitary, circumscribed, ulcerated plaque. Micro: superficial-to-dermoepidermal-border epidermal hyperplasia, hyperkeratosis, parakeratosis, scattered bizarre dyskeratotic cells. A notable proportion of cases are associated with internal visceral cancers.

Erythroplasia of Queyrat — on the penile mucosa. Gross: pink, shiny, velvety-soft. Micro: thickened, acanthotic epidermis with variable dysplasia. Unlike Bowen’s disease, there is no association with internal malignancy.

Bowenoid papulosis — on the penile shaft/adjacent genital skin. Gross: solitary or multiple, shiny, red-brown papules. Micro: orderly epithelial maturation in hyperplastic epidermis, with scattered hyperchromatic/dysplastic cells.

Malignant Tumours: Squamous Cell Carcinoma

Incidence varies markedly by population: <1% of all male cancers in the US, but 3–4× more common in Black than White populations there; in some Asian, African, and Latin American countries, incidence reaches ~10% of all cancers. Strong HPV association (high-risk types 16 and 18, with viral DNA documented in malignant cell nuclei). Notably rare in Jews and Muslims who undergo early-life ritual circumcision (in India: rare in circumcised Muslims, higher in uncircumcised Hindus) — circumcision protects by preventing smegma accumulation, believed carcinogenic. Peak incidence age 45–60.

Morphology: Gross — located (descending frequency) on frenum, prepuce, glans, coronal sulcus; cauliflower-like/papillary or flat/ulcerating patterns. Micro: fungating and ulcerating types are generally well- to moderately-differentiated, resembling squamous cell carcinoma elsewhere in the body. Spreads via lymphatics to regional nodes; haematogenous visceral metastasis is uncommon, occurring only in advanced disease.

Clinical Relevance

• The Bowen’s-disease-vs-erythroplasia-of-Queyrat distinction is a compact, high-yield pair: nearly identical premalignant behaviour, but only Bowen’s disease carries an association with internal visceral malignancy — this single fact is the reason to pursue systemic cancer screening when Bowen’s disease is diagnosed, but not for erythroplasia of Queyrat.
• Circumcision’s protective effect against penile carcinoma is one of the clearer examples in pathology of a surgical/cultural practice directly altering cancer incidence through a well-understood mechanism (smegma accumulation prevention) — worth retaining as a case study alongside the HPV 16/18 link, since both point toward the same chronic-irritant/viral-carcinogenesis framework seen in cervical cancer.
• Giant condyloma’s positioning as a clinical-behaviour intermediate between benign condyloma and squamous cell carcinoma — despite histologically benign features — is a reminder that histologic benignity does not always predict clinical course; local recurrence and locally destructive growth can occur even without cytologic malignancy.
• Phimosis is worth remembering as a genuine risk factor for penile carcinoma (via impaired hygiene and chronic smegma exposure), not just a mechanical nuisance — this is the direct clinical link between an anatomic anomaly and a malignancy.

• Three premalignant lesions (Bowen’s disease, erythroplasia of Queyrat, bowenoid papulosis) compared side by side with the internal-malignancy-association distinguisher marked
• Squamous cell carcinoma’s sites of predilection on a penile diagram, ranked by frequency