Peripheral Nerve Sheath Tumor in the Upper Eyelid in a Dog

Background: Schwannomas are benign neurogenic tumours of peripheral nerves. They originate from Schwann cells, which form the neural sheath.Peripheral nerve sheath tumors are most commonly found on the head and neck regions of both dogs and people. Schwannomas are rarely observed in ophthalmic areas. When they occur, ocular Schwannomas are usually located in the orbit, uveal tract and conjunctiva. The occurrence of uveal schwannoma, a subset of PNST has been well documented in the veterinary literature. This is the first report of a palpebral PNST in the dog. The lip-to-lid flap is a feasible technique to reconstruct the upper eyelid following wide surgical removal of a tumor in the dog.Case: A 9-year-old, spayed female mixed-breed dog was referred for evaluation of a large mass involving the right upper eyelid for a duration of approximately one month. The inspection revealed sero-sanguinolent discharge and an oval-shaped mass occupying more than 70% of the right upper eyelid. The dog was alert and the ophthalmic and general physical examination did not revealed abnormalities. Ocular ultrasonography did not show significant findings. A fine-needle aspirate of the palpebral tumor was not elucidative, even so, a presumptive diagnosis of eyelid neoplasia was considered most likely. Excision of the entire mass with a 2 cm margin was performed. The third eyelid and dorso-medial bulbar conjunctiva were also removed. Upper eyelid reconstruction was performed based on a similar technique previously described in cats (lip-to-lid flap). As a result, neoplastic spindle cells exhibited immunoreactivity for S100 and intense cytoplasmic staining for vimentin, supporting the diagnosis of schwannoma. Fifteen days later, the margins of the subdermal pattern flap were healed and skin sutures were removed. On the last follow-up, 9 months post-surgery, the dog was visual, and the flap was well incorporated and covered the ocular surface. Ten months later, another large mass arising from the right inferior palpebral conjunctiva was observed. Once ultrasound revealed orbital invasion exenteration combined with orbitectomy were performed, and the defect was covered with an auricular axial pattern flap. Although the second tumor had the same histological and immunohistochemical characteristics of the first mass additional staining for Ki67 was used to investigate the biological behavior of both masses.Discussion: Reported eyelid neoplasms in dogs include adenomas and adenocarcinomas of the meibomian glands, melanomas, fibroma, fibrosarcoma, histiocytoma, mastocytoma, lipomas, papillomas, and squamous cell carcinomas. To the author´s knowledge, however, this is the first case description of a PNST affecting the eyelid in a dog. The histologic distinction between PNSTs and other spindle cell tumors, including myxosarcoma, fibrosarcoma, leiomyosarcoma, hemangiopericytoma, and melanoma can be challenging and requires immunohistochemical stainin. S100 is an acidic protein that identifies various nervous tissue cells, including Schwann cells, and the majority of canine PNSTs diffusely express this molecule. As in the case presented here, neoplastic cells of different ocular and adnexal structures were also positive for S100 and vimentin in all PNSTs previously reported in the veterinary literature. This is the first report of PNST affecting the eyelid in a dog. The lip-to-lid flap is a feasible technique to reconstruct the upper eyelid following wide surgical removal of a tumor in dogs. However, the authors suggest radical surgery combining orbitectomy, exenteration and a miocutaneous flap if PNST is diagnosed in the eyelids of dogs. They also caution once recurrence is possible and can be more aggressive.Keywords: lip-to-lid transposition, S100, vimentin, desmin, Ki67, dog

Severe Corneal Edema in a Dog Naturally Infected by Leishmania spp.

Background: Visceral leishmaniasis (VL) is an infectious disease caused by the protozoan Leishmania infantum that is transmitted to dogs and humans by sandflies. The incidence of eye injuries in VL is high. They occur in 20 to 81% of infected dogs and include blepharitis, granulomatous conjunctivitis, scleritis, keratitis, anterior uveitis, keratoconjunctivitis sicca, and secondary glaucoma. However, some dogs present only the clinical signs of eye damage. The main objective of this manuscript is to report a case of anterior uveitis with severe corneal edema in a dog with VL that underwent clinical and surgical ophthalmic treatments after miltefosine therapy.Case: An 8-month-old, intact male Labrador Retriever with brown fur presented with pruritus, diffuse desquamation, and conjunctival hyperemia on physical evaluation. On the basis of an ophthalmic examination, nodular conjunctivitis and uveitis were diagnosed in both eyes. Moreover, laboratory examination results showed hyperproteinemia, increased serum alkaline phosphatase activity, and positive reactions to immunochromatographic tests for VL. Clinical treatment was instituted from the moment of diagnosis, when miltefosine and allopurinol were prescribed. At the end of treatment, based on laboratory examination results, only allopurinol was prescribed at a lower dose than initially prescribed for treatment continuation. Topical medications (prednisolone eye drops and sodium hyaluronate) were recommended for the ophthalmic changes. One week after the start of topical treatment, the dog showed an improvement in eye inflammation but still had bilateral corneal edema. A hyperosmotic agent was prescribed to improve edema, and a surgical procedure was recommended if there was no improvement. The physician opted for the surgical procedure in one of the eyes that had not shown significant improvement after the clinical treatment.Discussion: VL is a zoonosis, and the domestic dog is the main reservoir. These animals often have dermatological conditions, and the ophthalmic changes observed can be unilateral or bilateral, with more than one change in the same eye. Lymphoplasmacytic or granulomatous anterior uveitis is the most prevalent change, as the uvea and conjunctiva are important lymphoid areas of the eye; this also explains the high incidence of uveitis and conjunctivitis in dogs with VL. In uveitis, corneal edema is driven by endothelial cell damage induced by prostaglandins, which interfere with the function of the endothelial pump and interrupt the normal dehydrated state of the cornea. Severe corneal edema can result in the formation of fluid-filled multifocal bubbles in the corneal stroma—a condition called bullous keratopathy. These bubbles accumulate under or inside the corneal epithelium, and they can burst spontaneously, leading to corneal erosions or ulcerations. Drug therapy with hyperosmotic agents could, in principle, reduce the formation of bubbles. Surgical options to decrease edema and blistering include a permanent conjunctival graft or thermokeratoplasty. Thermokeratoplasty induces the formation of superficial scars in the corneal stroma, applying multiple cauterization foci to the stroma exposed in the areas of bullous keratopathy and epithelial ulceration. In conclusion, the surgical therapeutic choice results in better visual quality in patients who do not respond well to clinical treatment

Peripheral nerve sheath tumor in the upper eyelid in a dog

Background: Peripheral nerve sheath tumors are most commonly found on the head and neck regions of both dogs and people. Schwannomas are rarely observed in ophthalmic areas. When they occur, ocular Schwannomas are usually located in the orbit, uveal tract and conjunctiva. The occurrence of uveal schwannoma, a subset of PNST has been well documented in the veterinary literature. PNST has never been observed in the eyelids of dogs. Therefore, the present report aimed to describe the surgical treatment and outcome of a PNST located in the upper eyelid of a dog. Case: A 9-year-old, spayed female mixed-breed dog was referred for evaluation of a large mass involving the right upper eyelid for a duration of approximately one month. The inspection revealed sero-sanguinolent discharge and an oval-shaped mass occupying more than 70% of the right upper eyelid. A presumptive diagnosis of eyelid neoplasia was considered most likely. Excision of the entire mass with a 2 cm margin was performed. The third eyelid and dorso-medial bulbar conjunctiva were also removed. Upper eyelid reconstruction was performed based on a similar technique previously described in cats (lip-to-lid flap). As a result, neoplastic spindle cells exhibited immunoreactivity for S100 and intense cytoplasmic staining for vimentin, supporting the diagnosis of schwannoma. Fifteen days later, the margins of the subdermal pattern flap were healed and skin sutures were removed. On the last follow-up, 9 months post-surgery, the dog was visual, and the flap was well incorporated and covered the ocular surface. Ten months later, another large mass arising from the right inferior palpebral conjunctiva was observed. Once ultrasound revealed orbital invasion exenteration combined with orbitectomy were performed, and the defect was covered with an auricular axial pattern flap. The second tumor had the same histological and immunohistochemical characteristics of the first mass. Both tumors expressed Ki67; however, the PI in the second mass was higher (7.9%) than the first (3.4%). Discussion: Reported eyelid neoplasms in dogs include adenomas and adenocarcinomas of the meibomian glands, melanomas, fibroma, fibrosarcoma, histiocytoma, mastocytoma, lipomas, papillomas, and squamous cell carcinomas. To the author’s knowledge, however, this is the first case description of a PNST affecting the eyelid in a dog. The histologic distinction between PNSTs and other spindle cell tumors, including myxosarcoma, fibrosarcoma, leiomyosarcoma, hemangiopericytoma, and melanoma can be challenging and requires immunohistochemical stainin. S100 is an acidic protein that identifies various nervous tissue cells, including Schwann cells, and the majority of canine PNSTs diffusely express this molecule. As in the case presented here, neoplastic cells of different ocular and adnexal structures were also positive for S100 and vimentin in all PNSTs previously reported in the veterinary literature. This is the first report of PNST affecting the eyelid in a dog. The lip-to-lid flap is a feasible technique to reconstruct the upper eyelid following wide surgical removal of a tumor in dogs. However, the authors suggest radical surgery combining orbitectomy, exenteration and a miocutaneous flap if PNST is diagnosed in the eyelids of dogs. They also caution once recurrence is possible and can be more aggressive

Preputial Reconstruction Combined with Graft in Dogs

Background: Preputial injuries are significant in the clinical routine. Traumas, conditions, and mass excision result in extensive and full-thickness defects that lead to chronic penile exposure and consequential injuries. Severe injuries may require preputial reconstructive surgery to restore function and aesthetics. The objective is to report the use of the preputial reconstruction technique using the caudal superficial epigastric axial standard flap associated with a single-stage, full-thickness oral mucosa graft in 3 dogs where the loss of the prepuce was significant. Cases: Three dogs were admitted to the Veterinary Teaching Hospital of UFMT with preputial lesions of different etiologies. All cases were referred for preventive reconstruction using a flap in the caudal axial epigastric pattern associated with a single-stage oral mucosa graft. In the 3 reported cases, changes that compromised surgical success, such as suture dehiscence, necrosis, or infection, were not observed during hospitalization. Cutaneous stitch dehiscence, however, was observed in all 3 cases. Dog 1. A small point of dehiscence and tissue necrosis was found and treated with chemical debridement and healed by second intention, which proved to be sufficient on the 30th day. Dog 2.  A half-moon rotation flap was performed, which closed the defect. Dog 3.  A new procedure using the reporting theme technique was necessary in order to cover the cranial portion of the foreskin. The dehiscence present in dogs 2 and 3 was significant. Flap retraction was observed in all 3 cases. In dogs 1 and 3, the retraction was slight, and the exposure of a small portion of the penile glans were observed, showing no changes that required intervention. In dog 2, retraction was important, leading to partial stenosis of the preputial ostium. A larger ostium was obtained by suturing the mucosa to the edge of the wedge. Considering the possibility of adhesion formation, “captons” were made in sterile silicone tubes, and sutures were placed in the dorsal and ventral aspects to prevent adherence of the oral mucosa graft located on the inside of the new foreskin. The captons were removed on the tenth post-operative day, revealing a good opening of the preputial orifice and adequate penile exposure. Discussion: The absence of a foreskin caused by trauma or surgical excision leads to chronic penile exposure, dryness, and ulcerations. The simple covering of the skin with an axial-type flap of the caudal superficial epigastric region tends to fail since only the graft edges are sutured into the abdominal skin. In these circumstances, the subcutaneous region on the penis is exposed and comes in direct contact with urine and the penile mucosa, causing the flap skin to grow to exacerbated retraction. The transplantation of a free-lip mucosa graft allows the subcutaneous region of the transposed skin flap to create adhesions in the fenestrated regions of the lip tissue through the formation of granulation tissue buds, which is performed in a single stage. The permanence of the penis protects the lower urinary system from the occurrence of infections relative to what is normally observed in cases where partial or total penile amputation is practiced in combination with adjunctive scrotal urethrostomy. Given the observations of the 3 cases described here, the technique of pre-facial reconstruction with an axial skin flap of the caudal superficial epigastric region, combined with free-labial mucosa graft, was found to be feasible for the single-stage foreskin technique, but that paraphimosis remanagement may be necessary when cutaneous portions of the penile skin caudal to the glans are removed. Keywords: prepuce, reconstruction, oral mucosa. Título: Reconstrução prepucial com uso de enxerto combinado em cães. Descritores: prepúcio, reconstrução, mucosa oral

Peripheral Nerve Sheath Tumor in the Upper Eyelid in a Dog

Background: Schwannomas are benign neurogenic tumours of peripheral nerves. They originate from Schwann cells, which form the neural sheath.Peripheral nerve sheath tumors are most commonly found on the head and neck regions of both dogs and people. Schwannomas are rarely observed in ophthalmic areas. When they occur, ocular Schwannomas are usually located in the orbit, uveal tract and conjunctiva. The occurrence of uveal schwannoma, a subset of PNST has been well documented in the veterinary literature. This is the first report of a palpebral PNST in the dog. The lip-to-lid flap is a feasible technique to reconstruct the upper eyelid following wide surgical removal of a tumor in the dog.Case: A 9-year-old, spayed female mixed-breed dog was referred for evaluation of a large mass involving the right upper eyelid for a duration of approximately one month. The inspection revealed sero-sanguinolent discharge and an oval-shaped mass occupying more than 70% of the right upper eyelid. The dog was alert and the ophthalmic and general physical examination did not revealed abnormalities. Ocular ultrasonography did not show significant findings. A fine-needle aspirate of the palpebral tumor was not elucidative, even so, a presumptive diagnosis of eyelid neoplasia was considered most likely. Excision of the entire mass with a 2 cm margin was performed. The third eyelid and dorso-medial bulbar conjunctiva were also removed. Upper eyelid reconstruction was performed based on a similar technique previously described in cats (lip-to-lid flap). As a result, neoplastic spindle cells exhibited immunoreactivity for S100 and intense cytoplasmic staining for vimentin, supporting the diagnosis of schwannoma. Fifteen days later, the margins of the subdermal pattern flap were healed and skin sutures were removed. On the last follow-up, 9 months post-surgery, the dog was visual, and the flap was well incorporated and covered the ocular surface. Ten months later, another large mass arising from the right inferior palpebral conjunctiva was observed. Once ultrasound revealed orbital invasion exenteration combined with orbitectomy were performed, and the defect was covered with an auricular axial pattern flap. Although the second tumor had the same histological and immunohistochemical characteristics of the first mass additional staining for Ki67 was used to investigate the biological behavior of both masses.Discussion: Reported eyelid neoplasms in dogs include adenomas and adenocarcinomas of the meibomian glands, melanomas, fibroma, fibrosarcoma, histiocytoma, mastocytoma, lipomas, papillomas, and squamous cell carcinomas. To the author´s knowledge, however, this is the first case description of a PNST affecting the eyelid in a dog. The histologic distinction between PNSTs and other spindle cell tumors, including myxosarcoma, fibrosarcoma, leiomyosarcoma, hemangiopericytoma, and melanoma can be challenging and requires immunohistochemical stainin. S100 is an acidic protein that identifies various nervous tissue cells, including Schwann cells, and the majority of canine PNSTs diffusely express this molecule. As in the case presented here, neoplastic cells of different ocular and adnexal structures were also positive for S100 and vimentin in all PNSTs previously reported in the veterinary literature. This is the first report of PNST affecting the eyelid in a dog. The lip-to-lid flap is a feasible technique to reconstruct the upper eyelid following wide surgical removal of a tumor in dogs. However, the authors suggest radical surgery combining orbitectomy, exenteration and a miocutaneous flap if PNST is diagnosed in the eyelids of dogs. They also caution once recurrence is possible and can be more aggressive.Keywords: lip-to-lid transposition, S100, vimentin, desmin, Ki67, dog

Severe Corneal Edema in a Dog Naturally Infected by Leishmania spp.

Background: Visceral leishmaniasis (VL) is an infectious disease caused by the protozoan Leishmania infantum that is transmitted to dogs and humans by sandflies. The incidence of eye injuries in VL is high. They occur in 20 to 81% of infected dogs and include blepharitis, granulomatous conjunctivitis, scleritis, keratitis, anterior uveitis, keratoconjunctivitis sicca, and secondary glaucoma. However, some dogs present only the clinical signs of eye damage. The main objective of this manuscript is to report a case of anterior uveitis with severe corneal edema in a dog with VL that underwent clinical and surgical ophthalmic treatments after miltefosine therapy.Case: An 8-month-old, intact male Labrador Retriever with brown fur presented with pruritus, diffuse desquamation, and conjunctival hyperemia on physical evaluation. On the basis of an ophthalmic examination, nodular conjunctivitis and uveitis were diagnosed in both eyes. Moreover, laboratory examination results showed hyperproteinemia, increased serum alkaline phosphatase activity, and positive reactions to immunochromatographic tests for VL. Clinical treatment was instituted from the moment of diagnosis, when miltefosine and allopurinol were prescribed. At the end of treatment, based on laboratory examination results, only allopurinol was prescribed at a lower dose than initially prescribed for treatment continuation. Topical medications (prednisolone eye drops and sodium hyaluronate) were recommended for the ophthalmic changes. One week after the start of topical treatment, the dog showed an improvement in eye inflammation but still had bilateral corneal edema. A hyperosmotic agent was prescribed to improve edema, and a surgical procedure was recommended if there was no improvement. The physician opted for the surgical procedure in one of the eyes that had not shown significant improvement after the clinical treatment.Discussion: VL is a zoonosis, and the domestic dog is the main reservoir. These animals often have dermatological conditions, and the ophthalmic changes observed can be unilateral or bilateral, with more than one change in the same eye. Lymphoplasmacytic or granulomatous anterior uveitis is the most prevalent change, as the uvea and conjunctiva are important lymphoid areas of the eye; this also explains the high incidence of uveitis and conjunctivitis in dogs with VL. In uveitis, corneal edema is driven by endothelial cell damage induced by prostaglandins, which interfere with the function of the endothelial pump and interrupt the normal dehydrated state of the cornea. Severe corneal edema can result in the formation of fluid-filled multifocal bubbles in the corneal stroma—a condition called bullous keratopathy. These bubbles accumulate under or inside the corneal epithelium, and they can burst spontaneously, leading to corneal erosions or ulcerations. Drug therapy with hyperosmotic agents could, in principle, reduce the formation of bubbles. Surgical options to decrease edema and blistering include a permanent conjunctival graft or thermokeratoplasty. Thermokeratoplasty induces the formation of superficial scars in the corneal stroma, applying multiple cauterization foci to the stroma exposed in the areas of bullous keratopathy and epithelial ulceration. In conclusion, the surgical therapeutic choice results in better visual quality in patients who do not respond well to clinical treatment

Preputial Reconstruction Combined with Graft in Dogs

Background: Preputial injuries are significant in the clinical routine. Traumas, conditions, and mass excision result in extensive and full-thickness defects that lead to chronic penile exposure and consequential injuries. Severe injuries may require preputial reconstructive surgery to restore function and aesthetics. The objective is to report the use of the preputial reconstruction technique using the caudal superficial epigastric axial standard flap associated with a single-stage, full-thickness oral mucosa graft in 3 dogs where the loss of the prepuce was significant. Cases: Three dogs were admitted to the Veterinary Teaching Hospital of UFMT with preputial lesions of different etiologies. All cases were referred for preventive reconstruction using a flap in the caudal axial epigastric pattern associated with a single-stage oral mucosa graft. In the 3 reported cases, changes that compromised surgical success, such as suture dehiscence, necrosis, or infection, were not observed during hospitalization. Cutaneous stitch dehiscence, however, was observed in all 3 cases. Dog 1. A small point of dehiscence and tissue necrosis was found and treated with chemical debridement and healed by second intention, which proved to be sufficient on the 30th day. Dog 2.  A half-moon rotation flap was performed, which closed the defect. Dog 3.  A new procedure using the reporting theme technique was necessary in order to cover the cranial portion of the foreskin. The dehiscence present in dogs 2 and 3 was significant. Flap retraction was observed in all 3 cases. In dogs 1 and 3, the retraction was slight, and the exposure of a small portion of the penile glans were observed, showing no changes that required intervention. In dog 2, retraction was important, leading to partial stenosis of the preputial ostium. A larger ostium was obtained by suturing the mucosa to the edge of the wedge. Considering the possibility of adhesion formation, “captons” were made in sterile silicone tubes, and sutures were placed in the dorsal and ventral aspects to prevent adherence of the oral mucosa graft located on the inside of the new foreskin. The captons were removed on the tenth post-operative day, revealing a good opening of the preputial orifice and adequate penile exposure. Discussion: The absence of a foreskin caused by trauma or surgical excision leads to chronic penile exposure, dryness, and ulcerations. The simple covering of the skin with an axial-type flap of the caudal superficial epigastric region tends to fail since only the graft edges are sutured into the abdominal skin. In these circumstances, the subcutaneous region on the penis is exposed and comes in direct contact with urine and the penile mucosa, causing the flap skin to grow to exacerbated retraction. The transplantation of a free-lip mucosa graft allows the subcutaneous region of the transposed skin flap to create adhesions in the fenestrated regions of the lip tissue through the formation of granulation tissue buds, which is performed in a single stage. The permanence of the penis protects the lower urinary system from the occurrence of infections relative to what is normally observed in cases where partial or total penile amputation is practiced in combination with adjunctive scrotal urethrostomy. Given the observations of the 3 cases described here, the technique of pre-facial reconstruction with an axial skin flap of the caudal superficial epigastric region, combined with free-labial mucosa graft, was found to be feasible for the single-stage foreskin technique, but that paraphimosis remanagement may be necessary when cutaneous portions of the penile skin caudal to the glans are removed. Keywords: prepuce, reconstruction, oral mucosa. Título: Reconstrução prepucial com uso de enxerto combinado em cães. Descritores: prepúcio, reconstrução, mucosa oral