Zoon's balanitis
Synonyms and keywords: ZB, Plasma cell balanitis

# Overview
Zoon's balanitis is a rare non-veneral idiopathic chronic benign inflammatory mucositis of genitalia. In 1952, for the first time in medical literature, Zoon recognized a distinct entity in patients with chronic balanitis,and named it has balanoposthite chronique circonscrite benigne a plasmocytes or balanitis chronica circumscripta plasmacellularis. The exact pathogenesis of Zoon's balanitis is not clearly known. Patients with Zoon's balanitis presents with well circumscribed single or multiple orange-red in colour lesions with  characteristic glazed appearance and multiple pinpoint redder spots "cayenne pepper spots" most commonly involving glans penis. Diagnosis of Zoon's balanitis is confirmed by biopsy. Management of Zoon's balanitis includes both medical and surgical modalities.

# Historical Perspective
- In 1952, for the first time in medical literature, Zoon recognized a distinct entity in patients with chronic balanitis, named it has balanoposthite chronique circonscrite benigne a plasmocytes or balanitis chronica circumscripta plasmacellularis.
- In 1954, Garnier reported similar lesions in vulva.
- In 1956, Nikolowski described identical lesions in oral mucosa.
- In 1963, Kortnig described idential lesions in conjunctiva.

# Classification
There is no established classification system for Zoon's balanitis.

# Pathophysiology

## Pathogenesis
The exact pathogenesis of Zoon's balanitis is not clearly known, but following theories have been postulated:
- Accumulation of epithelial debris and secretions between foreskin and penis proximal to coronal sulcus, smegma, poor genital hygiene, repeated local infections, and hot and humid weather results in chronic physical irritation or sub-clinical trauma. Chronic physical irritation or sub-clinical trauma in-turn results in skin lesions along the line of trauma.
- Chronic infection with Mycobacterium smegmatis and human papillomaviruses (HPV) was found to be associated with development of Zoon's balanitis.

### Histopathology
Zoon's balanitis has distinctive histopathological features, which include:

### Epidermal
- Epidermal changes include early thickening with acanthosis and parakeratosis of epidermis, which is followed by atrophy, erosion and spongiosis of epidermis.
- Scattered neutrophils may be found in superficial erosions of the epidermis.
- Spongiosis accentuation may occur in the lower half of spinous zone.
- Subepidermal clefts, necrotic keratinocytes, and lozenge keratinocytes may be seen in the later stages of Zoon's balanitis.

### Dermal
- Dermal changes include patchy lichenoid infiltrate of lymphocytes and plasma cells in papillary dermis, which are replaced by  neutrophils, eosinophils, lymphocytes and erythrocytes.
- Dermal  vascular dilatation with singular vertical or oblique orientation of proliferated individual vessels is a characteristic feature of Zoon's balanitis.
- In the later stages, upper dermis may show fibrosis which correlates well with sub-epidermal clefts, epidermal atrophy, and plasma cell infiltrates.

# Epidemiology and Demographics
There are no comprehensive studies studying the epidemiology and demographics of Zoon's disease in general population. A recent study has reported that out of 226 patients examined in a genitourinary medicine clinic over a period of 3 years, about 26(10%) of patients were diagnosed with Zoon's balanitis.

# Screening
There is no established screening guidelines for Zoon's balanitis.

# Natural History, Complications, and Prognosis

## Natural history
If left untreated, patients with Zoon's balanitis may develop pain, phimosis and paraphimosis. Studies have reported that there could be an increased risk of transformation of these lesions into squamous cell carcinoma.

## Complications
Complications of Zoon's balanitis include:
- Phimosis
- Paraphimosis
- Risk of transformation into malignancy(Squamous cell carcinoma)

## Prognosis
Prognosis is usually good with treatment.

# Diagnosis

## History and symptoms
Patients with Zoon's balanitis could present with asymptomatic or symptomatic lesions with:
- Itching (pruritis) in the genitalia region
- Discomfort in urination(dysuria)
- Pain in the genital region
- Blood stain discharge from the lesions
- Difficult or painful sexual intercourse

## Physical examination
Characteristic lesions seen in Zoon's balanitis are:
- Well circumscribed single or multiple, orange-red in colour lesions with characteristic glazed appearance and multiple pinpoint redder spots "cayenne pepper spots"(please click here to view the image) most commonly affecting the  glans penis. Inner surface of prepuce and coronal sulcus may also be involved.
- Though uncommon, lesions of Zoon's balanitis may also involve other sites which include labia minora in females, oral mucosa, conjunctiva, urethra, cheeks, and epiglottis.
Clinical criteria for diagnosing Zoon's balanitis include the following:
- Shiny, erythematous patches on the glans, prepuceor both
- Lesions present for more than 3 months
- Absence of lesions which are suggestive of Lichen planus or psoriasis elsewhere on the body
- Poor response to topical therapies
- Absence of concurrent infections which are ruled out after performing tzanck, potassium hydroxide, gram stain and VDRL test

## Laboratory findings
Laboratory findings in Zoon's balanitis include:
Reflectance confocal microscopy
A nucleated honeycomb pattern and vermicular vessels is a clue for benign inflammatory genital skin disease
Dermoscopy
Focal/diffuse orange-yellowish structure with fewer areas representing hemosiderin deposition and curved vessels due to epidermal thinning help in distinguishing ZB from carcinoma in situ.

### Biopsy
Epidermal thickening which is followed by epidermal atrophy, at times with erosions
Dermis
Plasma cell infiltrate with haemosiderin and extravasated red blood cells.

# Treatment
Management of Zoon's balanitis includes general measures, medical and surgical modalities:

## General measures
Good hygiene which include retracting the foreskin regularly and gentle cleansing of entire glans, preputial sac, and foreskin were found effective in treating Balanitis in general.

## Medical Therapy

## Surgery

# Prevention

## Primary Prevention
There is no established primary prevention measures for preventing of Zoon's balanitis.

## Secondary prevention
There is no established secondary prevention measures for Zoon's balanitis.