Multi-system progressive angiomatosis in a dog resembling blue rubber bleb nevus syndrome in humans

Vertebral Angiomatosis in a Dog

A 3 yr old spayed female Cavalier King Charles spaniel was referred for insidious ataxia and paraparesis. A thoracolumbar lesion was suspected. Computed tomography showed focal osteolysis of the vertebral body and pedicles of T5. In addition, a hyperdense, extradural material within the vertebral canal, causing spinal cord compression on the right side, was present. The lesion was confirmed with magnetic resonance imaging. A T4-T5 hemi-dorsal laminectomy was performed to decompress the spinal cord. Histopathological examination was consistent with vertebral angiomatosis. After the surgery, the dog rapidly improved; however, 5 mo later the clinical signs relapsed. Vertebral angiomatosis is a vasoproliferative disorder, rarely reported as a cause of myelopathy in cats. This condition has not previously been reported in dogs. This case report describes the clinical features, the diagnostic findings, and the follow-up of a young dog with vertebral angiomatosis.

Progressive angiomatosis, resembling human skeletal-extraskeletal angiomatosis, arising in multiple digits in two dogs

Two dogs presented with progressive, expansile and invasive lesions on a hind paw. Case 1, a 10-year-old female Shetland sheepdog had diffusive and aggressive-looking lesions on the middle digits of the left hind paw. Radiographic examination showed invasion into and destruction of the underlying bone. A malignant tumour was suspected initially; however, histological features of atypical vascular proliferations without mitotic activity were consistent with progressive angiomatosis. Case 2, an 11-year-old female English springer spaniel presented with similar lesions in the same toes, also involving bone. Progressive angiomatosis was suspected clinically, as tumour cells were not detected by cytology and screening did not detect metastatic disease. Histopathology confirmed the diagnosis. Progressive angiomatosis is an uncommon non-malignant condition which should be considered as a differential diagnosis for radiographically lytic digital lesions.

Identification of Histopathological Criteria for the Diagnosis of Canine Cutaneous Progressive Angiomatosis

Simple Summary

In animals, cutaneous progressive angiomatosis (CPA) is a disorder with variable prognosis related to the extension and depth of infiltration of the surrounding tissues by vessels. CPA may share some microscopical features with other vascular proliferations such as low-grade well-differentiated capillaritic hemangiosarcoma (HS), making the diagnosis not always straightforward. The aim of this study is to assess the most common diagnostic microscopical features of CPA in dogs. Eleven histopathological criteria were analyzed on 31 CPA and 11 primary cutaneous HS in dogs. Features significantly associated with CPA included: lobular growth, interposition of connective tissue and adnexa between the vascular proliferation, presence of nerve fibers, and a mixed vascular proliferative component. Absence of plump/prominent endothelial cells, lack of atypia, and lack of mitoses were also significant factors for differentiating CPA from HS. In conclusion, the presence and/or absence of multiple microscopical clues allowed for the distinction of CPA from HS.

Abstract

The term angiomatosis is used to denote a group of well-known to poorly characterized proliferative vascular entities. In animals, cutaneous progressive angiomatosis (CPA) is a disorder with variable prognosis related to the extension and depth of infiltration of the surrounding tissues by vessels. CPA may share some microscopical features with other vascular proliferations such as low-grade well-differentiated capillaritic hemangiosarcoma (HS), making the diagnosis not always straightforward, especially in small biopsies. The aim of this study is to retrospectively assess the most common diagnostic microscopical features of CPA in dogs. In this work, 11 histopathological criteria were analyzed on 31 CPA and 11 primary cutaneous HS in dogs. Features significantly associated with CPA included: lobular growth, interposition of connective tissue and adnexa between the vascular proliferation, presence of nerve fibers, and a mixed vascular proliferative component. Absence of plump/prominent endothelial cells, lack of atypia, and lack of mitoses were also significant factors differentiating CPA from HS. Additional distinctive findings in CPA, although with no statistical association to CPA diagnosis, were vascular shunting, absence of necrosis, and endothelial cell piling up. In conclusion, the combined use of different microscopical clues allowed for the distinction of CPA from HS and was considered useful for the diagnosis of CPA.

Retroperitoneal lymphatic malformation in a dog

Background

Lymphatic vascular malformations are rare findings in canine patients with six reports available in veterinary literature. Retroperitoneal cystic lymphatic malformations have not been described previously in canine patients and neither has the use of immunohistochemistry to determine their origin, i.e. vascular versus lymphatic.

Case presentation

An 8-year-old neutered female Cocker spaniel was referred for pollakiuria, dysuria and a painful abdomen. Computed tomography scanning of the abdomen showed a fluid filled structure adjacent to the urinary bladder. During surgical exploration, a thin walled cystic structure with sero-haemorrhagic fluid was found, extending from the retroperitoneal space into the abdomen. The mass was excised and submitted for histopathology, revealing a cystic mass lined by a fibrovascular capsule within the retroperitoneal/mesenteric adipose tissue. The inner surface of the cyst was lined by a single layer of bland, flattened spindle cells. Intramural blood vessels were well differentiated, with perivascular haemorrhage. On recurrence 11 months later, the mass was excised for the second time and a PleuralPort (Norfolk Animal products) was placed. Fifteen months after initial presentation, progression occurred with haemorrhagic fluid in the cystic space, pleural- and abdominal cavities and the owners opted for euthanasia. Histopathology and positive immunohistochemistry for lymphatic markers lymphatic vessel endothelial hyaluronic acid receptor-1 (LYVE-1) and prospero homeobox protein-1 (PROX-1) confirmed a lymphatic vascular origin of the cystic structure.

Conclusions

To our experience, a definitive diagnosis of retroperitoneal cystic malformation of lymphatic origin could be done only by combining the clinical presentation, advanced imaging, histopathology and LYVE-1 and PROX-1 immunohistochemistry. This is the first report of a vascular malformation in a dog where immunohistochemistry was used to make a final diagnosis. A lymphatic malformation, even if rare, should be added on the list of the differential diagnosis in a patient with a retroperitoneal cystic structure containing serohaemorrhagic fluid. Results of this case report can aid in diagnosis of future cases, however, further studies on therapy and management are needed to provide additional information about optimal treatment of these patients.

Feline vertebral angiomatosis: two cases

CASE SERIES SUMMARY

Two cats aged between 1 and 2 years were presented for paraparesis, general discomfort, back pain and urinary retention. Extradural spinal cord compression at the level of T4 and T8 was evident on CT examination and on MRI. Hemilaminectomy and partial corpectomy were performed to achieve spinal cord decompression. Histopathology of the abnormal bone tissue was suggestive of vertebral angiomatosis. After initially worsening, both cats recovered their normal gait and functional urination. Both cats have been followed-up for >1 year, without any recurrence.

RELEVANCE AND NOVEL INFORMATION

This is the first report of vertebral angiomatosis with complete data (CT, MRI, surgical procedures, histopathology and >1 year follow-up) and provides important information about the prognosis of this rare vascular malformation.