PA28.{2,6} | Penile Carcinoma & Male Genital Morphology — Summary & Reflection

REFLECT

Before you close this SDL, take 5 minutes and try this exercise:

Mentally walk through a pathology practical station where you are shown 5 slides/specimens one after another — a testis tumor, a prostate gland, a penile lesion, a histology of a glandular prostatic lesion, and a microscopy of a squamous lesion with keratin pearls. For each one, ask yourself:

1. What is the single most characteristic gross feature that narrows my diagnosis?
2. What is the single most characteristic microscopic feature?
3. Which HPV type (if relevant) or IHC marker distinguishes it?

If you can answer all three for each disease in the summary table above without looking, you are practical-exam ready. If not — which one is still hazy? Go back to that block now. The examiner will ask a follow-up question; your answer to the follow-up is where marks are made or lost.

KEY TAKEAWAYS

Key take-aways from this SDL:

Penile pathology — the HPV spectrum:
• HPV 6/11 → condyloma acuminatum (koilocytes, papillary, benign)
• HPV 16/18 → PeIN (full-thickness dysplasia, intact BM) → invasive SCC
• Bowen (shaft, keratotic) vs erythroplasia of Queyrat (glans, red/moist) — same histology, different site
• Penile SCC risk factors: HPV, non-circumcision, phimosis, smoking
• Gross types: papillary (exophytic) vs ulcerative (endophytic, worse prognosis)
• Histology: keratin pearls + invasive nests = well-differentiated keratinizing SCC
• Spread: superficial inguinal → deep inguinal (Cloquet) → iliac nodes; node status = most important prognostic factor

Practical morphology — recognition rules:
• Seminoma: homogeneous cream-white + lymphocytic stroma + clear cells
• NSGCT: variegated (hemorrhage + necrosis + cysts) — look for component-specific features (Schiller-Duval body for YST)
• BPH: nodular, transition zone, two-cell layer, corpora amylacea
• Prostatic adenocarcinoma: peripheral zone, NO basal layer, prominent nucleoli, perineural invasion; Gleason 3 (individual glands) vs 4 (fused/cribriform) vs 5 (sheets)
• IHC: AMACR+/HMWCK− = carcinoma; AMACR−/HMWCK+ (basal) = BPH

Three numbers to remember: HPV 6/11 (condyloma), HPV 16/18 (SCC). Gleason 3+4 vs 4+3 matters — 4+3 has worse prognosis than 3+4 even with same score of 7.