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Rare disease
Immunohistochemical analysis of a merkeloma observed in a patient affected by hereditary haemorrhagic telangiectasia
  1. Elisa Rossi1,
  2. Laura Boeri2,
  3. Patrizia Morbini3,
  4. Fabio Pagella4,
  5. Andrea Colombo4,
  6. Elina Matti4,
  7. Carla Olivieri2,
  8. Vincenzo Villanacci1,
  9. Antonella Minelli2,
  10. Elisabetta Buscarini5,
  11. Cecilia Canzonieri2,
  12. Cesare Danesino6
  1. 1Spedali Civili di Brescia, Second Department of Pathology, Piazzale Spedali Civili, 1, Brescia, 25123, Italy
  2. 2University of Pavia, Medical Genetics, Via Forlanini, 14, Pavia, 27100, Italy
  3. 3University of Pavia, IRCCS Policlinico S. Matteo, Pavia, Pathological Anatomy Department, Via Forlanini, 14, Pavia, 27100, Italy
  4. 4IRCCS Policlinico S. Matteo, Pavia, ENT Unit, Via Golgi, 19, Pavia, 27100, Italy
  5. 5Ospedale Maggiore of Crema, Gastroenterology Unit, Via Macall, Crema, 26013, Italy
  6. 6University of Pavia, Via Forlanini, 14, 27100 Pavia, Pavia, 27100, Italy
  1. Correspondence to Cesare Danesino, cidilab{at}


Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterised by epistaxis, telangiectases, and multiorgan vascular dysplasia. Mutations of the ENG and ACVRL1 genes cause at least 80% of cases. We report the first case of merkeloma found in a patient with HHT carrying an ENG mutation. We analysed the tumour with immunohistochemical methods using primary antibodies against CD105 (endoglin), TGF-β, Smad4, CD31 and CD34. Tumour cells were positive for Smad4, weakly positive for TGF-β, and negative for CD105. Vasal endothelial cells were highly positive for CD105, CD31 and CD34. No remarkable differences between cancer and normal cells in our patient or between the patient’s merkeloma and two control merkelomas were observed. The presence of a merkeloma in an HHT patient could be an occasional association, but to certainly assume it further investigations are needed.

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  • Competing interests: None.

  • Patient consent: Patient/guardian consent was obtained for publication.

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