What is the diagnosis and management for an erythematous patch on the glans penis in a male patient?

Erythematous Patch on Glans Penis: Diagnosis and Management

An erythematous patch on the glans penis requires biopsy to establish diagnosis before initiating treatment, as this presentation encompasses multiple conditions ranging from benign inflammatory dermatoses to premalignant and malignant lesions. 1

Immediate Diagnostic Approach

Essential Clinical Assessment

• Examine the entire integument and genital region to identify whether this is an isolated penile lesion or part of a systemic dermatological disease 2, 3
• Document specific lesion characteristics: exact location (glans, prepuce, coronal sulcus), diameter, morphology (papillary, nodular, ulcerous, or flat), presence of erosion, hyperkeratosis, white plaques, or atrophic changes 4
• Assess for phimosis or foreskin retractability, as inability to fully examine the glans increases risk of undetected pathology by 25-60% 5
• Obtain detailed history: duration of lesion, associated symptoms (pain, pruritus, dysuria), sexual history, prior treatments attempted, history of lichen sclerosus, psoriasis, or other dermatoses 2, 3

Mandatory Biopsy Indications

Biopsy is essential before initiating treatment in the following scenarios: 1

• Any diagnostic uncertainty
• White, smooth atrophic plaques suggesting lichen sclerosus
• Persistent hyperkeratosis or erosion
• Failure to respond to empiric treatment
• Any suspicion of premalignant change or malignancy

Differential Diagnosis Framework

Inflammatory/Infectious Conditions

• Plasma cell balanitis (Zoon balanitis): Single, shiny, well-defined reddish patch in uncircumcised men, typically benign but chronic 6
• Erosive lichen planus: Erythematous and erosive lesion with sero-fibrinous exudations, may be steroid-resistant 7
• Lichen sclerosus: Grayish-white discoloration, atrophic plaques, may progress to phimosis and urethral involvement 4, 5, 1
• Candida/bacterial balanitis, contact dermatitis, psoriasis: Consider based on clinical presentation and patient history 2

Premalignant/Malignant Conditions

• Penile carcinoma in situ (Tis): Erythematous patch that may represent early malignancy 4
• Extramammary Paget's disease: Rare intraepidermal adenocarcinoma presenting as erythematous plaque 8
• Invasive squamous cell carcinoma: Risk factors include phimosis, chronic inflammation, lichen sclerosus, HPV, smoking 4

Management Algorithm

Step 1: Obtain Tissue Diagnosis

Perform punch, excisional, or incisional biopsy of the lesion to confirm diagnosis and rule out malignancy before initiating any treatment 4, 1

Step 2: Treatment Based on Histopathology

If Lichen Sclerosus Confirmed:

• Apply clobetasol propionate 0.05% ointment once daily for 1-3 months plus emollient as soap substitute 9, 5
• If phimosis prevents topical application, introduce steroid using cotton wool bud or refer for circumcision 9
• Monitor every 6-12 months indefinitely due to 2-9% risk of malignant transformation 5, 1
• Circumcision may be needed for severe disease, but 50% continue to have lesions post-circumcision requiring ongoing maintenance with 30-60g clobetasol annually 9

If Penile Carcinoma In Situ (Tis):

Penile-preserving techniques are preferred: 4

• Topical imiquimod 5% or 5-FU cream
• Wide local excision (including Mohs surgery)
• Laser therapy (carbon dioxide or Nd:YAG) - category 2B
• Complete glansectomy - category 2B for extensive disease

If Erosive Lichen Planus:

• Ultrapotent topical corticosteroids as first-line 1
• For steroid-resistant cases: cyclosporin A 3 mg/kg daily with monitoring of renal and hepatic function 7
• Circumcision may be considered after medical control achieved 7

If Plasma Cell Balanitis:

• Circumcision is often curative for this benign condition 6
• Differentiate from syphilitic chancre, especially in patients with STI history 6

Step 3: Surveillance Strategy

For Treated Carcinoma In Situ:

• Year 1-2: Clinical exam every 3 months
• Year 3-5: Clinical exam every 6 months
• Year 5-10: Clinical exam every 12 months 4

For Lichen Sclerosus:

• Lifelong monitoring every 6-12 months even when asymptomatic 1
• Biopsy any new suspicious areas immediately 1

Critical Pitfalls to Avoid

• Never initiate treatment without tissue diagnosis when presentation is atypical or diagnosis uncertain 1
• Do not assume benign inflammatory condition in patients with risk factors for penile cancer (phimosis, lichen sclerosus, HPV, smoking, chronic inflammation) 4, 5
• Always send circumcision specimens for histological examination to exclude penile intraepithelial neoplasia 9, 5
• Do not discontinue surveillance after successful treatment of lichen sclerosus due to ongoing malignancy risk 5, 1
• Recognize that lichen sclerosus in children has been misdiagnosed as sexual abuse, causing unnecessary family trauma 1