Diagnostic difficulty-an elusive case of Hansen ́s disease mimicking sarcoidosis

Hansen ́s disease (leprosy) is caused by a slow-growing type of bacteria called Mycobacterium leprae (M. leprae). It is an age-old disease that has been around since biblical times yet cases still occur especially in Asia and Africa, despite concerted global efforts to eradicate the disease. Chemotherapeutic agents are available and effective once administered appropriately and adequately. We report an elusive case of Hansen ́s disease wherein the only symptom was a nodule on the nasal bridge in an otherwise healthy woman for over one year. Repeated examinations and investigations in different centers were suggestive of sarcoidosis and she was left untreated for leprosy for the period. A skin biopsy was carried out for histopathology diagnosis. Histology confirmed borderline lepromatous leprosy. This case demonstrates the need for a definitive diagnosis of leprosy to reduce the spread of this contagious disease especially in tune with the concerted global efforts. Case report | Volume 2, Article 122, 19 Mar 2020 | 10.11604/pamj-cm.2020.2.122.20622 Available online at: https://www.clinical-medicine.panafrican-med-journal.com/content/article/2/122/full ©Erere Otrofanowei et al PAMJ Clinical Medicine (ISSN: 2707-2797). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Case report PAMJ Clinical Medicine ISSN: 2707-2797 (www.clinical-medicine.panafrican-med-journal.com) The Manuscript Hut is a product of the PAMJ Center for Public health Research and Information.


Introduction
Hansen´s disease-also known as leprosy is a chronic infectious disease caused by a bacterium Mycobacterium leprae and it is well known for its stigma and lasting sequelae. Eradication of this disease has been a target of the World Health Organisation (WHO) for decades and whilst successes have been recorded, a few largely populated countries still record high prevalence and incidence rates. This may be related to both late and difficult diagnoses. This case report highlights a typical example of the latter with an initial diagnosis of sarcoidosis and emphasizes the need for a highly specific and sensitive laboratory tests to achieve total eradication.

Patient and observation
A 68 year old female petty trader from the south-western parts of Nigeria was referred from another centre with a single non-itchy, non-painful rash on the bridge of her nose that had slowly increased in size to involve her upper lip over a 1 year period. The only associated symptom was rhinorrhea. There were no lesions on any other part of the body. There was neither a positive family history nor other contact history of similar lesions. On physical examination, she had a flesh-coloured plaque on the inferior end of the nasal bridge involving the tip of the nose and the philtrum, effectively flattening the septum and causing a saddle-nose deformity ( Figure 1). There were few smaller flesh-coloured plaques on the malar region of the right half of her face. There was a non-tender solitary hyperpigmented plaque on the right nape posteriorly, about 6cm in size and was not scaly. All lesions had intact sensation and no loss of skin appendages. All other systems were normal, though blood pressure was elevated at 180/80mmHg for which she was taking Lisinopril tablets.  [4]. Skin lesions are seen in almost 25% of sarcoid patients and can be classified into specific or non-specific depending on the presence (or not) of non-caseating granulomas on histologic specimen [5,6]. The confusion between cutaneous sarcoid and leprosy is limited to tuberculoid leprosy as the lepromatous end of the spectrum has more distinct features both physically and histologically. There are actually some schools of thought that the mycobacterium causing leprosy may be an inciting agent of sarcoidosis [2,7], but this has not been generally accepted.
The diagnosis of leprosy is via a combination of compatible clinical features and the demonstration of characteristic caseating granulomas on histopathology carried out on well-developed skin lesions. The presence of acid fast bacilli in the dermis provides even more evidence but is not always seen especially in the tuberculoid end of the Ridley-Jopling spectrum [8]. Unfortunately, histopathology is not readily available in this part of the world and reliance on less sensitive tests as elevated ESR, skin slit and smears to demonstrate AFB (negative in 70% of cases) [9], lepromin tests, allows for delayed diagnosis and treatment which results in lepromatous presentation as cell-mediated immunity decreases. This is noted in the index case as initial tests carried out (when she had just a solitary hypopigmented patch on the face) were all negative. Serum ACE levels can be elevated in leprosy as well as sarcoidosis, but it is also seen in other diseases as histoplasmosis, Gaucher´s disease, HIV infections, lymphomas and so on. The need for early diagnosis of leprosy cannot be over emphasized and a new diagnostic tool for this is being developed by the U.S.-based Infectious Disease Research Institute (IDRI) and OrangeLife, a Brazilian medical products company [10]. It is said to yield results in less than 10minutes in a manner similar to a pregnancy test kit which makes it easy to use by community clinics and primary health care workers.
If this is made available worldwide, especially to endemic countries, the world may well be on its way to eradicating this age-old disease neglected tropical disease.

Conclusion
The initial presentation of leprosy in the index patient was subtle enough to elude diagnosis both clinically and with investigations. This contributed to worsening of symptoms and the possibility of increased disease transmission.
Recognition of early symptoms, rapid and reliable means of diagnosis are to be emphasized and promoted at the community clinics and primary healthcare centres to achieve a reduced incidence rate in endemic countries.   Ziehl-Nielsen special stain