Pathology case studies :Granular cell tumour in an 8-year-old Pomeranian
Cystitis Glandularis in a 13-year-old female cat
Pathology Case Study
By Dr Marvin J. Firth, Anatomic Pathologist at NationWide Laboratories, BVSc (Hons.), DipRCPath, DipFMS, AFHEA, MRSB, MRCVS
A mass that was attached to the underside of the tongue in an 8-year-old Pomeranian was noted on clinical examination by the primary veterinarian. This was surgically removed and sent for histopathological evaluation to NationWide Laboratories.
The tissue was composed of typical skeletal muscle and oral epithelium consistent with that of the tongue, yet focally there is also extensive ulceration. The underlying connective and muscular tissue is effaced and infiltrated by a densely cellular, unencapsulated, poorly demarcated mass. The mass is composed of sheets of densely packed, round to polygonal cells supported by a fibrovascular stroma (see Fig 1.).
These neoplastic cells have variably distinct borders, often eccentrically placed round nuclei with abundant eosinophilic granular cytoplasm. There was mild to moderate pleomorphism of the cells and low mitotic activity. Unfortunately, the mass extends to the deep and lateral margins of the sections examined. Additional staining of the tissue with periodic acid Schiff (PAS), shows fine PAS positive granules within the cytoplasm of neoplastic cells (seen in Fig 2 and 3).
The findings of the histopathology and additional stains confirmed the presence of a granular cell tumour of the tongue of this dog. These are fairly uncommon, yet benign tumours found in the skin and subcutis, oral cavity or even the central nervous system, as well as a common tumour in the lung of horses. The name is descriptive and does not imply a specific cell of origin or differentiation, which is, yet, unknown in these tumours. Immunohistochemistry adds little additional information as to the cell of origin, but these tumours tend to be well demarcated, nonencapsulated and have variable amounts of collagenous stroma. Most granular cell tumours are benign and complete surgical excision is curative.
The clarity afforded by the 3D Histech system allows pathologists to see the greatest of detail at both a tissue and cytoplasmic level of the neoplastic cells. This enables us to make more informed and accurate diagnoses of tumours that may not have additional tests to confirm their histogenesis. In this case, we are also able to accurately report surgical margins with software tools that accurately measure and outline the neoplastic against the normal tissue.
Read more case studies from NationWide Laboratories
By Karina Fresneda, Anatomic Pathologist at NationWide Laboratories, DVM DiplACVP
Cystitis is a clinically significant disease that affects various species, with a higher incidence in females, likely linked to their shorter urethra. This condition can manifest as either acute or chronic. Chronic cystitis takes on diverse forms based on the pattern and type of inflammatory response, including diffuse, follicular, and polypoid variants.
Chronic polypoid cystitis is characterized by the presence of polypoid masses, particularly common in dogs but may occur in any species. These masses likely develop as an inflammatory and hyperplastic response to chronic irritation, often stemming from persistent bacterial urinary tract infections (UTIs) and/or uroliths.
The polyps found in the bladder mucosa consist of a core of proliferative connective tissue covered by surface epithelium. This surface epithelium can form nests of hyperplastic urothelial cells in the lamina propria, known as Brunn’s nests, or undergo metaplasia to a mucus-secreting, glandular epithelial type, leading to a condition called Cystitis Glandularis.
These resulting polypoid masses may have a broad-based or pedunculated structure, occurring most frequently in the cranioventral bladder wall. Chronic haematuria, often unresponsive to antimicrobial therapy, is a common observation in cases of chronic polypoid cystitis. This bleeding is often associated with the breakdown of polyps, potentially promoting urine retention and bacterial introduction, thus establishing a cyclic pattern of infection, proliferation, and inflammation.
Histologically, our case had in lamina propria, occasionally extending from mucosa, multiple hyperplastic tortuous glands that were often cystic dilated. They were lined by one to multiple layers of uniform cuboidal or columnar epithelial cells, occasionally surrounded by a few layers of urothelial cells. They had no evident atypia. The lamina propria where they were immersed contained a few plasma cells, lymphocytes, neutrophils and rare histiocytes.
References:
1.Cystitis glandularis in a cat. Amalia Agut, Juana D Carrillo, Marta Soler, Juan D Garcia, Eliseo Belda, Miguel A Gomez and Antonio Bernabe. Journal of Feline Medicine and Surgery. Volume 16, Issue 4, April 2014, Pages 363-365.
2. Cystitis Cystica, Cystitis Glandularis, and Brunn’s Nests in a Feline Urinary Bladder. J. F. Zachary. Veterinary pathology Journal. Volume 18, Issue 1.
3. Pathology of domestic animals. Volume 2. Jubb, Kennedy & Palmer’s. Sixth edition. 2016. p459-461
4. Pathologic basis of veterinary disease. James F. Zachary. Seventh edition. 2022. p 762
