Multiple apocrine hydrocystomas in feline: intralesional application of 20% trichloroacetic acid - case report

[Múltiplos hidrocistomas apócrino em felino: aplicação intralesional de ácido tricloroacético 20% - relato de caso]

ABSTRACT

Hidrocystomas are well-defined, firm to fluctuant, pigmented nodules measuring 2 to 10mm in diameter. They develop on both the upper and lower eyelids and may be located at the medial and/or lateral canthi of the eyelids. Classified as a benign tumor, its origin may derive from apocrine sweat glands such as the glands of Moll. The definitive diagnosis occurs through histopathological analysis. The objective was to report a case of multiple apocrine hidrocystomas in a feline treated with intralesional injection of 20% trichloroacetic acid (TCA). A 12-year-old Persian feline, with a history of blackish-colored nodules on the palpebral fissure of both eyes, which had already been removed by excision surgery and had recurred, was treated. Clinical suspicion of apocrine hidrocystoma was raised based on the patient’s history. The surgical removal of a nodule for histopathological analysis and the application of 20% TCA to the remaining nodules were recommended. The patient was discharged 21 days after the surgical procedure with full recovery. Hidrocystomas may present recurrences when treated only with surgical excision. However, the application of 20% TCA presented satisfactory results in the total remission of these neoplasms and kept the patient stable without signs of recurrence for 12 months of monitoring.

Keywords:
hydrocystoma; palpebral rima; feline; trichloroacetic acid 20%; relapses

RESUMO

Os hidrocistomas são nódulos, bem circunscritos, firmes a flutuantes, pigmentados, podendo medir de 2mm a 10mm de diâmetro. Eles se desenvolvem tanto nas pálpebras superiores quanto nas inferiores, podendo estar localizados nos cantos medial e/ou lateral das pálpebras. Classificado como tumor benigno, sua origem pode derivar de glândulas sudoríparas apócrinas, como as glândulas de Moll. O diagnóstico definitivo ocorre pela análise histopatológica. Objetivou-se, neste estudo, relatar um caso de múltiplos hidrocistomas apócrinos em felino, tratados com injeção intralesional de ácido tricloroacético (TCA) 20%. Foi atendido um felino, raça Persa, 12 anos de idade, com histórico de conter nódulos de coloração enegrecida em rima palpebral de ambos os olhos, os quais já tinham sido retirados por exérese cirúrgica e recidivaram. Com o histórico do paciente, levantou-se suspeita clínica de hidrocistoma apócrino, preconizando a remoção cirúrgica de um nódulo para análise histopatológica e aplicação de TCA 20% nos demais nódulos. O paciente recebeu alta 21 dias após procedimento cirúrgico com total recuperação. Os hidrocistomas podem apresentar recidivas quando tratados somente com exérese cirúrgica; todavia, a aplicação do TCA 20% apresentou resultado satisfatório na remissão total dessas neoplasias, bem como manteve o paciente estável, sem sinais de recidivas, por um período de doze meses de monitoramento.

Palavras-chave:
hidrocistoma; rima palpebral; felino; ácido tricloroacético 20%; recidiva

INTRODUCTION

Hidrocystoma is a circumscribed dermal neoplasm composed of one or more cystic structures of variable size, which are generally covered by a single layer of columnar to cuboidal epithelial cells (Gruchouskei et al., 2017). Classified as a benign tumor, its origin may derive from eccrine sweat glands, located under the skin of the eyelid, or apocrine sweat glands, which develop next to hair follicles (Casali et al., 2015). In the eyelids, apocrine glands are called glands of Moll, are present next to the eyelashes, and represent between 3 and 7% of feline eyelid neoplasms (Chaitman et al., 1999).

There are theories about the development of hidrocystomas by obstruction of the excretory duct (Shields et al., 1993) or a proliferative process due to papillary projections from the cyst wall, therefore considering it a cystadenoma (Smith and Chernosky, 1974). This palpebral neoplasia is considered rare and has a predisposition in Persian felines of any sex or age (Chaitman et al., 1999; Giudice et al., 2009; Cantaloube et al., 2011; Kahane et al., 2014; Pigatto et al., 2022). It is also reported in the Domestic Shorthair and Himalayan breeds (Pigatto et al., 2016), in addition to a report describing hidrocystoma in the abdominal region of a melanic jaguar (Gruchouskei et al., 2017).

Clinical signs of palpebral hidrocystoma will depend on the size and location of the cysts and may include blepharospasm, tearing, conjunctival hyperemia, and ocular secretion, in addition to its clinical manifestation (Kahane et al., 2014). The suggestive diagnosis is clinically based on its phenotypic morphology, filtering tumor possibilities with fine needle aspiration cytology (FNAC) (Cantaloube et al., 2011) and defining the diagnosis through histopathological analysis after excisional biopsy (Gruchouskei et al., 2017). Therapeutic alternatives include surgical excision, aspiration drainage, liquid nitrogen cryosurgery, and chemical ablation (Yang et al., 2007).

Cases of recurrence after therapy with only surgical excision have been reported in the same location and other regions of the body (Chaitman et al., 1999). In humans, intralesional injection of 20% trichloroacetic acid (TCA) has been used successfully (Dailey, 2005). However, in veterinary medicine, only one case has been reported in felines by Pigatto et al. (2022). Due to both factors, the objective was to report a case of multiple apocrine hidrocystomas in a Persian feline treated with an intralesional injection of 20% trichloroacetic acid.

A 12-year-old castrated male Persian feline weighing 4.5kg with a history of blackish-colored nodules on the palpebral fissure of both eyes was treated. During the anamnesis, the owner reported that the patient had already tested negative for Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV). The vaccination and deworming records were up to date and the animal had been presenting normal appetite, normal thirst, normal urination, and normal defecation. The animal underwent previous treatment to remove these nodules, but the owner reported recurrence in the same locations after 4 months.

The general physical examination showed the physiological variables within the species standard. During the specific ophthalmological examination, the patient presented blepharospasms in both eyes, in addition to two dark-colored nodules in the medial canthus of the left eye and four nodules in the medial canthus of the right eye associated with scarring leukoma at the 4 o'clock position. No signs of conjunctival hyperemia or presence of secretion were observed, in addition to showing no neuro-ophthalmic changes after carrying out the tests. Tear production and intraocular pressure were measured using the Schirmer^® Test (Oftálmica Manipulação, Porto Alegre, RS, Brazil) and Tonovet Plus^® (Ícare Tonovet, Finlandia, Oy, Europe), respectively, and showed values within the reference for the species (17 mm/min - VR: 15-30mm/min; 16 mmHg - VR: 15-25mmHg). The fundus of the eye was evaluated by indirect ophthalmoscopy with a Volks lens after applying Tropicamide^® 10 mg/ml eye drops (Alcon, Geneva, Switzerland) in both eyes, showing a halangiotic pattern already expected for feline patients.

Clinical suspicion of hidrocystoma was raised based on the findings, patient history, and identification. The surgical removal of a nodule for histopathological analysis and the application of manipulated 20% Trichloroacetic Acid (TCA) to the remaining nodules were recommended. Blood samples were collected from the right external jugular vein to prepare a blood count and serum biochemistry with measurement of creatinine, urea, alkaline phosphatase (AP), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), albumin, globulins, and total proteins. All results presented standards within normal limits for the species. Subsequently, due to the patient’s calm temperament, a trichotomy of the necessary areas was performed, and venous access was established for anesthetic induction with Propovan^® (propofol 4 mg/kg, IV; Cristália Produtos Químicos Farmacêuticos, Itapira, SP, Brazil), followed by endotracheal intubation for maintenance in a semi-closed circuit with vaporized isoflurane.

Antisepsis of the peribulbar region of both eyes was performed with 1% povidone-iodine (PVPI) solution, removing the smallest nodule in the right medial canthus with a scalpel #3 and blade #11 (Fig. 1A-B). Then, the sample was sent to the laboratory of histopathology. The surgical wound was sutured with Vycril^® 6-0 synthetic absorbable thread (Ethicon Company Page - J&J MedTech, São Paulo, SP, Brazil) in a simple isolated pattern. The remaining nodules were subjected to puncture with an insulin syringe for aspiration of the cystic content associated with the application of Trichloroacetic Acid (TCA)® 20% (Dinâmica Química Contemporânea Ltda, Indaiatuba, SP, Brazil). The applied volume of 20% TCA was equal to the aspirated cystic content, maintaining the acid for 2 minutes and subsequently removing the same injected volume. After recovery from anesthesia, the patient was discharged from the hospital with systemic medication based on Maxicam^® (0.1mg/kg, SID, for 3 days, V.O. Agener União Saúde Animal, São Paulo, SP, Brazil), Dipirona^® 500 mg/ml (25mg/kg, TID, for 5 days, V.O. Medley Farmacêutica, Suzano, SP, Brazil), and topical medication with application of ointment based on neomycin and hydrocortisone (Maxitrol^®, QID, for 14 days; Alcon, Geneva, Switzerland). The patient was evaluated 24 hours after surgery with no complications, returning weekly to monitor clinical evolution.

Healing of the lesions and slight peeling were observed 7 days after surgery. There were no signs of peeling on the 14th day and the stitches were removed. The patient was clinically discharged 21 days after the surgical procedure with full surgical access recovery (Fig. 1C-D).

Figure 1
Nodules in the right (A) and left (B), where the arrow is showing nodules that will be excised for histopathological analysis. Right (C) and left (D) eyes after described treatment.

30 days after the patient's discharge, the histopathological report confirmed all nodules as hydrocystomas of apocrine glands (Fig. 2A-B), whose report described cysts in both mucocutaneous junctions (eyelids) covered by one or two layers of columnar cells (dilation apocrine cystic disease). The cells had abundant and finely granular eosinophilic cytoplasm, in addition to a round nucleus, formed by aggregated chromatin and located basally (H&E obj.10x). With the result and the patient's history of recurrences, quarterly follow-up visits were established for the patient, totaling 12 months without signs of hydrocystoma recurrence (Fig. 2C-D).

Figure 2
Image at 10x magnification of the nodule surgically removed for histopathological analysis (A) and the same image with electronic magnification (zoom) (B). Right eye (C) and left eye (D) 12 months after surgery, showing no signs of recurrence of hydrocystomas.

DISCUSSION

Hidrocystomas are multiple, well-defined, firm to fluctuant, pigmented nodules measuring 2 to 10 mm in diameter. They develop in both the upper and lower eyelids and may be in the medial and/or lateral canthi of the eye but most commonly originate in the medial canthus (Chaitman et al., 1999) and have no hair on their surface (Little, 2012). The patient had multiple nodules with the characteristics described in the literature, located in the medial canthi of both eyes, corroborating the described predisposition, as observed for a patient of the Persian breed, already identified as the main breed for its development (Chaitman et al., 1999; Giudice et al., 2009; Cantaloube et al., 2011; Kahane et al., 2014; Pigatto et al, 2022).

For diagnosis, FNAC reveals the presence of translucent, dark brown fluid, with the presence of neutrophils and macrophages in variable proportions (Cantaloube et al., 2011). In the case in question, FNAC was not performed, but the cystic content was dark brown in color and fluid in consistency at the time of aspiration of the hidrocystomas before the application of 20% TCA. Only one of the neoplasms was removed excisionally and sent for histopathological analysis.

In this case, histopathological analysis described the cyst with apocrine cystic dilatations lined by one or two layers of columnar cells, which encompass the lining epithelial tissue. According to Gruchouskei et al. (2017), hydrocystomas must present several layers of lining cells, small glandular structures between the cysts or protruding from their walls, which may or may not contain simple papillary aggregates or branches of columnar epithelial cells. Therefore, through the histopathological report, it was possible to confirm the diagnosis of Apocrine Gland Hydrocystomas in the feline reported in this case, a crucial factor in establishing the patient's prognosis, since the presentation of hydrocystomas has several tumor differential diagnoses that would not have a satisfactory result through application of TCA 20%.

The development of this neoplasm can be monitored if there is no ocular discomfort, as it is benign. However, surgical excision of isolated masses and aspiration of cystic contents can be performed as treatment and can also be complemented with cryosurgery or chemical ablation using 20% trichloroacetic acid (Yang et al., 2007). The reported patient had previously undergone surgical procedures to remove the nodules but had developed tumor presentations again. Due to this history, location, and clinical presentation of the nodules, we decided to apply 20% TCA to evaluate its effectiveness relative to recurrences, generating satisfactory results for 12 months.

The patient had no complications in the perioperative period after the therapeutic procedures. Like any blepharoplasty, surgical treatment can lead to complications such as entropion due to shortening of the eyelid during cyst excision (Kahane et al., 2014; Dailey, 2005), resulting in corneal ulcers, tearing, and blepharospasms (Pigatto et al, 2022). There was no need for severe plastic correction due to the excision of the smallest nodule, not harming the anatomy of the patient’s eyelids. Therefore, there were no complications related to the 20% TCA or surgical procedure.

CONCLUSION

Hidrocystomas may present recurrences when treated only with surgical excision. However, the application of 20% trichloroacetic acid showed satisfactory results in the total remission of these neoplasms and kept the patient stable without signs of recurrence for 12 months of monitoring. Therefore, the application of 20% TCA can be further explored in veterinary medicine due to its therapeutic effectiveness and no side effects or complications in the peri-operative period.

ACKNOWLEDGMENTS

We thank the Coordination of the Federal Agencies for the Improvement of Higher Education Personnel (CAPES), Brazil - Financial Code 001, and the National Council for Scientific and Technological Development (CNPq), Brazil. We also thank Qualem Laboratório Veterinário for the histopathological analysis and sharing of images, as well as the University Veterinary Hospital of the Federal University of Santa Maria (HVU-UFSM) and its Veterinary Ophthalmology and Microsurgery Sector (SOMVET) for the satisfactory resolution of the case in question.

REFERENCES

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Publication Dates

• Publication in this collection
  14 July 2025
• Date of issue
  Jul-Aug 2025

History

• Received
  29 July 2024
• Accepted
  25 Nov 2024