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Pathology of Confluent and Reticulated Papillomatosis  - Top 10 Facts

Dr Sampurna Roy MD 




Key histological features of Confluent and reticulated papillomatosis

(i) undulating basket-weave hyperkeratosis,

(ii) papillomatosis,

(iii) focal acanthosis limited to the areas of rete ridge elongation, and

(iv) increased basal melanin pigmentation.

Labelled diagram showing all the features of Confluent and reticulated papillomatosis


Clinical and Microscopic Images of Confluent and Reticulated Papillomatosis ( Click on the images for enlarged view)






Confluent and reticulated papillomatosis of Goujerot-Carteaud is a rare and benign skin disease of unknown etiology characterized by flat papules taking a reticulated appearance.


Confluent and reticulated papillomatosis (CRP) was first described by Gougerot and Carteaud in 1927. They named this lesion "papillomatose pigmentée innominée". They presented further cases and subsequently renamed the condition papillomatose pigmentée confluente et réticulée in 1932. In 1937, Wise and Sachs introduced the term confluent and reticulated papillomatosis.


The cause is not known. Could be related to keratinization disorder, abnormal response of the individual follicular bacteria, or Malassezia.  Associations with endocrine disorders, such as obesity, type 2 diabetes mellitus, hirsutism, Cushing's syndrome, menstrual abnormalities, and thyroid dysfunction have been suggested.

According to some authors there is could be a link with vitamin A deficiency, genetic factors, photosensitivity and cutaneous amyloidosis.


The lesions are located in the inter-scapular, epigastric and intermammary regions, sparing, in general, the mucosae and palmoplantar areas. In extensive cases it may affect the neck, shoulders, axillae and pubic areas.

5) Age and sex

It is more frequent among the female, nonwhite race, and obese patients. This lesion is usually noted in teenagers and in the second or third decades of life.

6) Clinical Presentation

Asymptomatic lesion, but has been described to be pruritic in some individuals.

It is limited only to the skin with no systemic involvement.

Confluent and reticulated papillomatosis typically manifests as multiple 1 to 2mm erythematous papules that become brownish hyperkeratotic 4  to 5mm papules. These papules may coalesce centrally to form plaques while demonstrating a peripheral reticulate pattern.

7)Microscopic features:

Histopathological features include:

(i) undulating basket-weave hyperkeratosis,

(ii) papillomatosis,

(iii) focal acanthosis limited to the areas of rete ridge elongation, and

(iv) increased basal melanin pigmentation.

It has been suggested that papillomatosis may not be present in early CRP.

8) Differential diagnosis:

There is a wide array of dermatoses that may resemble CRP. The closest mimic in terms of distribution and appearance is Acanthosis Nigricans. Histologically, these two conditions can be distinguished based on the features mentioned. Pityriasis versicolor is also commonly included in the differential diagnosis.

9) Electron microscopy and immunohistochemistry:

Electron microscope and immunohistochemical studies show abnormal keratinocyte differentiation, increased transition cell layer, and increased lamellar granules in the stratum granulosum. There is increased melanosomes in the stratum corneum. Involucrin, keratin 16, and Ki-67 expression are increased.

10) Diagnostic criteria by Davis et al. Confluent and reticulate papillomatosis (Gougerot-Carteaud syndrome): a minocycline-responsive dermatosis without evidence for yeast in pathogenesis. A study of 39 patients and a proposal of diagnostic criteria.  

(i) clinical findings of scaly brown macules and patches, with at least some appearing reticulated and papillomatous;

(ii) involvement of the upper trunk and neck;

(iii) negative fungal staining of scales;

(iv) no response to antifungal treatment; and

(v) excellent response to minocycline.


Further reading:

Confluent and reticulated papillomatosis: diagnostic and treatment challenges

Confluent and reticulate papillomatosis of Gougerot-Carteaud and obesity: dermoscopic findings

Confluent and Reticulated Papillomatosis of Gougerot-Carteaud on Black Skin: Two Observations

Updated Diagnosis Criteria for Confluent and Reticulated Papillomatosis: A Case Report

Confluent and reticulated papillomatosis manifested as vertically rippled and keratotic plaques




Dr Sampurna Roy  MD

Consultant  Histopathologist (Kolkata - India)








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