Tucumã tree thorn granuloma

Abstract

Barco da Saúde (Health Boat) is a project of the University of São Leopoldo Mandic that aims to bring voluntary medical and dental care to communities bordering the Tapajós River, in the state of Pará, Brazil. In its 4th edition in 2023, 134 dermatological treatments were carried out, most of them inside the hospital boat. Many patients were farmers and fishermen, exposed to the occupational risks inherent to these activities in the Brazilian Amazon region. Of the work carried out by riverside dwellers, we highlight the harvest of tucumã, the fruit of the tucumã tree, which is a typical palm tree from the Amazon region that belongs to the genus Astrocaryum. Its striking feature is the presence of black, flexible thorns in almost all parts of the plant,¹ which can reach 15 cm in length. Its fruit is of great socioeconomic importance for the Amazon population. Several families survive thanks to the extraction of this fruit. Tucumã, in addition to being used in oil extraction, is highly appreciated in local cuisine and can be consumed fresh. It is rich in beta-carotene and flavonoids and Brazilian cosmetics companies are adding tucumã to their products for its alleged antioxidant capacity.²

We describe the case of a 34-year-old male patient who is a black farmer from the Açaiatuba Community in Pará, Brazil. The patient reported that 3 years earlier he had fallen on a tucumã tree and that several thorns had injured his arms. He extracted the thorns from the skin manually but after a few months he noticed a nodule on his left forearm. Physical examination revealed a nodule measuring approximately 3 × 2 cm, normochromic, moveable, not deeply attached and slightly painful on palpation on the extensor surface of the left forearm. Suspecting a foreign body granuloma (FBG), a surgical approach was chosen. Macroscopic analysis of the surgical specimen revealed material with a pointed shape and a blackish colour. On microscopic analysis, histological sections stained with hematoxylin-eosin revealed chronic inflammation with eosinophils, associated with a focus of necrosis and the presence of plant cells (Figure 1), confirming the diagnosis of FBG added to allergic reaction.

FBG, also called non-immunological granuloma, is a tissue reaction that develops due to the penetration of substances through the skin accidentally or on purpose.³ FBG is caused by substances that are unable to elicit a specialised immune response (mediated by T lymphocytes). On histopathological examination, FBG is characterised by the presence of identifiable foreign material, surrounded by histiocytes, multinucleated giant cells and a variable number of other inflammatory cells.⁴ Some authors propose that plant induced injuries, particularly cactus spines, can additionally induce an allergic reaction to vegetal antigens, because not every patient develops granulomatous lesions.⁵ In our patient, histology was consistent with a FBG added to allergic reaction, with eosinophils, giant cells and chronic lymphocytic infiltrate around it. Vegetal induced granuloma may last up to 9 months if untreated.⁶ The long duration in our patient was related with poor medical care accessibility.

Due to the geographic restriction of tucumã tree and few reports of medical assistance to this population, we do not have data on frequency or histology of similar accidents. As the Amazonian products become more commercially attractive, it is important to know and report the occupational dangers in this area. This case report shows a patient with limited access to health care who was diagnosed with exogenous FBG (tucumã tree thorn) acquired 3 years earlier during his work activity.

Carolina Viza Amorim: study concept, data collection, writing of the manuscript. Jéssica Barbosa Camargos Dias: data collection. Vitória Jugni: data collection. Mirella Pinotti: data collection. Icléia Siqueira Barreto: data collection, analysis and interpretation. Fernanda Oliveira Camargo Herreros: analysis and interpretation, critical review, research guidance, approval of the final version of the manuscript. All authors have approved the final article version.

The authors declare no conflicts of interest.

All patients in this manuscript have given written informed consent for participation in the study and the use of their de-identified, anonymized, aggregated data and their case details (including photographs) for publication. Ethical Approval: not applicable.