Pott Puffy Tumour: A Case to Look Beyond the Nose

An 85-year-old man presented with a painless lesion on the bridge of the nose that had been present for 6 months. He described that the lesion started as a large lump with pus and blood oozing from it. As with previous treatments, we note topical disinfectant products and various antibiotic treatments, none of which have led to a cure. The patient felt well and reported no other complaints. During clinical examination, we saw a sunken erythematous erosive lesion that was noticeably adherent to the surrounding tissue on palpation (Figure 1). This made us want to rule out a connection with underlying structures (such as the bone/sinuses). A sinus CT (Figure 2) was performed and showed chronic frontal sinusitis and a Pott puffy tumour (PPT). To rule out the possibility that it was a coincidental combination of chronic sinusitis and a malignancy, a biopsy (Figure 3) of the lesion was taken, which showed reactive changes with a hyperplastic epidermis and a florid dermal infiltrate with an important plasmocytic component without atypia. Additional immunohistochemical staining for kappa and lambda light chains showed a normal kappa/lambda ratio, demonstrating the polyclonal nature of the plasma cells. There was no histological evidence for underlying epithelial or haematological malignancy. PPT is a rare diagnosis. It is characterised by the presence of a subperiosteal abscess arising from frontal bone osteomyelitis. Sir Percival Pott first described the condition in 1768 and referred to the observable swelling with the word ‘tumour’ (one of the four components of inflammation), rather than to neoplasia. It is characterised by a circumscribed, tender swelling at the forehead mostly presenting with other associated symptoms including fever, headache, nasal discharge or increased intracranial pressure. Most frequently, it is a complication of acute or chronic sinusitis. Other possible causes are head trauma, dental infection, cocaine abuse and head surgery [1]. Various bacteria can be associated with PPT, with the most frequent being nonenterococcal streptococci (47%), anaerobic oral bacteria (28%) or staphylococci (22%) [1]. The type of bacteria involved influences how quickly symptoms appear. Organisms such as Actinomyces and anaerobes tend to cause slower onset of symptoms compared to more aggressive microbes like Staphylococcus aureus or those causing mucormycosis, which lead to faster symptom development [2]. The differential diagnosis of a frontal swelling includes epidermoid cyst, musculus frontalis-associated lipoma, dermoid cyst, infected haematoma and benign or malignant tumours of the skin, bone or frontal sinuses [3]. Because of the high frequency of intracranial complications, PPT can be life-threatening. As soon as there is suspicion, rapid imaging (CT or MRI) should be obtained [4]. A bacterial swab is also recommended to guide subsequent antibiotic treatment. Treatment consists of a combination of intravenous, broad-spectrum antibiotics with good penetrance through the blood–brain barrier and surgery to drain the abscesses, debride necrotic tissue and restore sinus drainage [1]. Our patient was referred to the colleagues of otorhinolaryngology for further approach. They suggested either performing an endoscopic sinus intervention for drainage under general anaesthesia or a conservative approach with wound care given the patient's age and lack of complaints. With this unique case, we would like to emphasise that PPT can also occur in an otherwise symptom-free patient and that this rare entity should also be considered in the case of erosive lesions in the frontal region, as there was no more visible swelling in our patient at the time of consultation. Virginie Lucidarme conceptualised and wrote the article. Erwin Suys and Michiel Bonny reviewed and provided critical feedback on the manuscript. Stephanie Verschuere provided us with the histological images with accompanying descriptions. All patients in this manuscript have given written informed consent for participation in the study and the use of their deidentified, anonymized, aggregated data and their case details (including photographs) for publication. The authors declare no conflicts of interest. The authors have nothing to report.