Introduction
Granuloma is a chronic inflammatory reaction triggered by a wide variety of persistent agents, characterized by the recruitment and activation of macrophages, occasionally presenting areas of central necrosis [1,2]. They often present a firm, tumor-like granulation with a collection of inflammatory cells and epithelioid cells. The common cause could be linked to bacterial, fungal, and viral infections such as mycobacterium, aspergilus species, and papilloma virus, respectively [2,3]. Other incriminated risks are foreign bodies, genetic factors, and environmental agents such as aluminum hydroxide, or may also be idiopathic [1,4–6].
Persistent reactions induced by exposure to aluminum-containing compounds/products have been linked to the development of local and systemic manifestations in a variety of species including cats, ferrets, dogs, and sheep [2,6]. Granuloma-associated multi-systemic chronic infection causes several types of production losses and limitations to the trade of live animals [2,4]. While exfoliative cytology and histology are sufficient for the confirmation of granulomas, radiography using computed tomography has been reported useful as a noninvasive diagnostic tool for internal granulomatous lesions [1,2].
Case Management
History and clinical examination
A 5-year-old Uda ewe, weighing 41kg was presented to the Large Animal Clinic of the University of Jos Veterinary Teaching Hospital (UJ-VTH) in September, 2023, with the complaint of a large mass around the right jugular furrow. History revealed that the mass was noticed 2 years before presentation with an observed marked increase in size over the past 2 months. Also, no medical intervention of any sort had been instituted. Clinical examination revealed rectal temperature, pulse rate, and respiratory rate of 39.8°C, 80.0 beats/minute, and 24.0 cycles/minute, respectively. Upon further examination, there was slight congestion of the ocular mucous membrane, the mass was firm and tumor-like in consistency with areas of healed ulcer on the surface, and the right submandibular lymph nodes were enlarged.
Management
Blood samples and fine needle aspirate of the swelling were collected and sent to the Clinical pathology laboratory for hematological and cytological evaluation according to the methods first described by Robinson et al. [7] (Table 1 and Fig. 1). The surgery was performed by the general surgical team led by a veterinary surgical oncologist in the large animal surgical theater of the University of Jos Veterinary Teaching Hospital, Plateau State, Nigeria. The right side of the neck region was prepared for aseptic surgery by clipping the hair around the area, scrubbing using chlorhexidine gluconate (Purit®), and applying mild antiseptic. Total excisions of the mass were performed under local anesthesia (local infiltration with 1% Lidocaine hydrochloride (Swiss Pharma PVT Ltd, Gujarat, India) following mild sedation using 2% Xylazine (Alfasan, Woerden-Holland) at 0.1mg/kg. Specimen of the excised mass was immediately fixed in 10% neutral buffered formalin for 24–72 hours., washed under flowing water, dehydrated in ascending grades of alcohol, cleared in xylol, and then embedded in paraffin wax. Five (5) μm thickness sections were cut and stained with Harries hematoxylin and eosin stains [13]. The prepared slides were examined under a light microscope (Olympus Research microscope, CH20i binocular version, Shinjuku, Tokyo, Japan with AmScope 10MP USB microscope digital camera + calibration kit, Mainland, China) with objective 10 x and 40 x for subsequent interpretation (Fig. 2). The resulting defect was closed by primary intention with routine wound cleansing and care instituted thereafter. Post-operative medications included the administration of 0.2% Dexamethasone, 0.11 mg/kg IM as an anti-inflammatory agent, 1% Piroxicam 0.6 mg/kg IM x2/7 Q48 hours. as an analgesic agent, and 20% Amoxicillin LA 20mg/kg (4 mls) IM x2/7 Q48 hours. as antibiotics; against resident bacteria and secondary bacteria invasion. Also administered were, Multivitamins 4 mls IM x2/7 Q48 hours. for its critical nourishing role in tissue repair, speeding up recovery, and Tetanus toxoid (TT) 0.5ml IM to protect the ewe from the dangerous disease; Tetanus, which could easily develop by picking up the ubiquitous Clostridium tetani from the environment. Follow-up re-examinations of the ewe were undertaken every other day with stitches removed on day 12 post-operation following the observation of neatly approximated wound edges with no exaggerated granulation tissue as expected of closure by primary intention. After 14 days of management, the ewe was discharged following normal rectal temperature (39.0°C), pulse rates (80.0 beats/minute), and respiratory rates (28.0 cycles/minute).
Table 1.
Hemogram.
| Parameters | Patients values | Reference range |
|---|---|---|
| HB (g/dl) | 11.00 | 9.00–15.00 |
| PCV (%) | 28.00 | 27.00–45.00 |
| WBC(×109/l) | 13.70 | 4.00–8.00 |
| Neutrophils (×109/l) | 11.10 | 0.70–6.00 |
| Lymphocytes (×109/l) | 2.00 | 2.00–9.00 |
| Monocytes (×109/l) | 0.30 | 0.00–0.75 |
| Eosinophils (×109/l) | - | 0.00–1.0 |
| Basophils (×109/l) | - | 0.00–0.30 |
| Plasma protein (g/dl) | 8.40 | 6.00–7.50 |
Reference: Hassan and Hassan [19].
L: litres, g/dl: gramme per deciliter.
Ethics statement
This case management is a part of the University of Jos VTH’s routine clinical case management, therefore, ethical approval for animal care and welfare was not required. Informed consent for publication was obtained from the client, along with permission from the head of the clinic unit.
Figure 1.
Gross and cytological appearance of granuloma from an Uda-Ewe. Gross appearances: (A) Gross Appearance of the granulomatous mass (white arrow) and (B) Surgically excised mass. Cytological appearance: (C) Impression smear showing giant cell (highlighted in back) with intracytoplasmic neutrophils (blue arrow) and (D) Impression smear showing plasma cells (Black arrow) and sulphur granules (a). Giemsa Stain (1,000×).
Figure 2.
Photomicrograph of granulomatous mass. Showing necrotic center with sulfur granules (a), area of microphages, lymphocytes, and plasma cell (b), and area of fibroconnective tissue (×10 obj. lens) Photomicrograph of mass showing necrotic center with sulfur granules (Highlighted) ×10 obj. lens Neovascularization (a) and perivascular cuffing (asterisk) around the connective tissue mass (×10 obj. lens) Showing inflammatory cells infiltration (×40 obj. lens).
Discussion
Granuloma is a benign noncancerous lump that can occur due to the aggregation of macrophages in response to inflammation and can be caused by infectious and noninfectious triggers. Infectious stimuli include bacteria such as Mycobacteria, parasites such as Schistosoma, and fungi such as Aspergillus. Noninfectious triggers include autoimmune disease, neoplasia, and foreign bodies such as sutures, among others [3–6,]. The diagnosis of granuloma in ewe in this case was based on history, clinical and pathological findings. The involved part of the neck was close to the jaw, thus the right submandibular lympadenopathy being the closest immune organ to the site. Sometimes, a fistula is formed with abscesses of the head bones resulting especially when complicated by infectious agents such as Actinobacillus lignieresii, Nocardia asteroides, and Staphylococcus aureus which were not incriminated in this case [8,9].
Cytological findings of impression smear from the cut surface showed vacuolated macrophages with phagocytized neutrophils. There were also plasma cells and lymphocytes as well as sulphur granules. These findings are likely the body’s response to chronic antigenic stimulants by the development of granulomas in an effort to contain the immunologic insult. They may also be formed in response to persistent diseases such as sarcodiosis, schistosomiasis, and infections caused by bacteria, fungi, and protozoa. Granulomas can develop in any organ of the body where the causative infectious agent resides [10–12]. They represent the body’s first line of response to infectious agents such as mycobacterium, thus, coupled with history and clinical signs they usually serve as a histopathological hallmark of these diseases [12–14].
Options available for the management of granulomas are varied with no clear consensus among surgeons and medical practitioners. The available options include; aggressive and prolonged administration of antibiotics and corticosteroids, surgical excision, cryotherapy, and cauterization using silver nitrate among others [15]. Although many patients respond well to corticosteroids, they may require prolonged course making it problematic as they are usually immuno-suppressive. Among these management options, surgical excision has been documented to offer the lowest overall recurrence rates of about 2.94% while cryotherapy offered the lowest recurrence in the medical treatment regimens. Surgical excision and primary closure appear to be preferred especially in noncosmetically sensitive areas; however, if nonsurgical management is undertaken, cauterization with silver nitrate should be the first line treatment with antibiotic administration as indicated [15–17]. If tumor necrosis factor-α (TNF-α) inhibitors such as infliximab are used as effective anti-inflammatory agents, there is a need for enhanced vigilance due to the significantly increased risk of severe and even fatal infections similar to the prolonged use of corticosteroids. In such cases, conventional treatment consists of lifelong anti-infectious prophylaxis with antibiotics such as trimethoprim-sulfamethoxazole, antimycotics such as itraconazole and/or interferon (INF)–gamma [16–18].
Severe neutrophilic leukocytosis and hyperproteinemia, in this case, may be attributed to chronic inflammatory responses and possible bacterial complications [1,2,8]. The combination of specialized immune cells including macrophages and neutrophils is influenced by an orchestrated pro- and anti-inflammatory response [10]. Granulomas of this type are indicative of the presence of chronic inflammation suggestive of a causative role of chronic irritation in the pathogenesis and have adverse effects on the productive function of the Ewe which only became pronounced with the increasing size of the tumor. Therefore, proper management practices favoring the exclusion of common predisposing factors such as bacterial, fungal, viral, and environmental agents such as aluminum hydroxide may reduce the risk of developing granulomas.
Acknowledgment
The author appreciates the immense contributions of Mr. G. James of the Pathology Department, Plateau Specialist Hospital, and Mr. Y. I. Abdulkareem of the Veterinary Biochemistry, Physiology, Pharmacology and Toxicology Department, University of Jos, Plateau state for assisting with the laboratory analysis.
Conflicts of interest
The authors declare they have no conflict of interest.
Funding
The authors declared that this study received no financial support.
Authors’ contribution
D.O. Avazi, P.I. Sambo, and H.O. Alo-Aleje contributed to the clinical case management, surgical intervention, and postoperative follow-up along with manuscript finalization. G.Y. Gurumyen and S.A. Hena assisted with the sample processing including cytology and histology slide preparation, and interpretation. All authors have read and approved the final manuscript.
