Dynamic tracheal collapse associated with disseminated histiocytic sarcoma in a cat

Comparison of the Trachea in Normocephalic versus Brachycephalic Cats on the Basis of CT-Derived Measurements

Tracheal hypoplasia is a major concern in brachycephalic dogs, but there is no consensus for the trachea in brachycephalic cats. We aimed to compare tracheal length and diameter between normo- and brachycephalic cats using computed tomography (CT) image measurements and evaluate their usefulness in tracheostomy planning. A total of 15 normocephalic and 14 brachycephalic cats were included in the study. Tracheas of normocephalic cats were significantly longer compared with brachycephalic cats. No difference was detected in tracheal diameter between normocephalic and brachycephalic cats. Both groups had a lateral diameter significantly larger than the dorsoventral diameter at the level of the cranial end of the manubrium sterni and at the level of the second rib. Normocephalic and brachycephalic cats' tracheas have the same dorsoventral flattening at the level of the cranial end of the manubrium sterni and at the level of the second rib. The location between the 4th and 5th cervical vertebrae seems the best place to perform a tracheostomy in cats due to its round shape and easily accessible anatomical location. No sign of tracheal hypoplasia in brachycephalic cats was detected. Finally, 7 mm appears to be an adequate diameter for the tracheal tubes used to perform feline tracheostomies.

Retrospective study of feline tracheal mass lesions

OBJECTIVES

This multicentre, retrospective observational study aimed to describe the clinical presentation, diagnostic methods, treatment and outcomes of cats with tracheal masses.

METHODS

Eighteen cats from five academic or secondary/tertiary animal hospitals were included.

RESULTS

The median age at diagnosis was 10.7 years (mean 9.5; range 1-17). There were nine castrated males, seven spayed females, one intact male and one intact female. Fourteen (78%) were domestic shorthairs, one (6%) was an Abyssinian, one (6%) was an American Shorthair, one (6%) was a Bengal and one (6%) was a Scottish Fold. The most common presenting complaints included chronic respiratory distress or dyspnoea (n = 14), followed by wheezing/gagging (n = 12), coughing (n = 5) and voice changes (n = 5). There was cervical tracheal involvement in 16/18, and two showed involvement of the intrathoracic trachea. The following methods were used for diagnosis: ultrasound-guided fine-needle biopsy (UG-FNB) and cytology (n = 8), bronchoscopic forceps biopsy and histopathology (n = 5), surgical resection and histopathology (n = 3), forceps biopsy via an endotracheal tube (n = 1) and histology of tissue sputtered from a cough (n = 1). Lymphoma was most often diagnosed (n = 15), followed by adenocarcinoma (n = 2) and squamous cell carcinoma (n = 1). Most lymphoma cases received chemotherapy with or without radiation according to various protocols, and partial (n = 5) or complete responses (n = 8) were noted. Kaplan-Meier survival data for cats with lymphoma revealed a median survival time of 214 days (95% confidence interval >149 days), which was significantly longer than that of other types of tumours (21 days).

CONCLUSIONS AND RELEVANCE

Lymphoma was the most prevalent diagnosis, and showed a good response to chemotherapy with or without radiation therapy. Various diagnostic procedures were performed, and UG-FNB and cytology are good diagnostic procedures for cervical tracheal lesions. Owing to the variety of treatment protocols at different centres, it was impossible to compare outcomes.

Self-expanding tracheal stent placement in a cat with primary tracheal collapse

A 12-year-old mixed-breed spayed female cat presented with dyspnoea, open-mouthed breathing, and cyanosis that was difficult to control with medical pharmacotherapy; the cat was diagnosed with the primary tracheal collapse of the neck and chest regions. The diagnosis was confirmed by dynamic chest radiography, tracheal endoscopy, and computed tomography (CT). Tracheal endoscopy and CT showed dropsy of the dorsal membranous wall over most of the trachea. A self-expanding Nitinol cross-and-hook braided stent was placed along the entire tracheal lumen using surgical X-ray fluoroscopy. Bacterial cultures in the trachea were negative. Dyspnoea disappeared immediately after the endotracheal stent was implanted. Although the long-term prognosis remains under observation, the short- to medium-term prognosis was very good. These results suggest that stenting may be useful in the treatment of primary tracheal collapse in cats.

Oral histiocytic sarcoma in a cat with mandibular invasion and regional lymph node metastasis

Case summary

An 11-year-old female spayed domestic medium-hair cat presented for dental prophylaxis, at which time no oral mass was appreciated. Fifteen days after a dental cleaning, a mass expanding the oral mucosa of the rostral mandible was identified. An incisional biopsy revealed that the oral mucosa was infiltrated by neoplastic round-to-spindloid mesenchymal cells arranged in streams and small, dense aggregates consistent with an undifferentiated sarcoma. The patient was managed medically for approximately 6 months following the diagnosis, but, owing to declining health, euthanasia was elected and a post-mortem examination was performed. On post-mortem examination, the previously described neoplastic cells were infiltrating the rostral mandible and had metastasized to the right submandibular lymph node. Immunohistochemistry performed during the postmortem examination found that neoplastic cells were positive for Iba-1, CD18 and CD204, and negative for MUM-1, S100, Melan-A and E-cadherin, favoring a diagnosis of oral histiocytic sarcoma. Although recently recognized in cats, feline oral histiocytic sarcoma is rare, the tumor’s immunohistochemical profile is unstandardized, and the tumor’s behavior and prognosis are unclear. The diagnosis is challenging if small incisional biopsies are submitted and the neoplasm is poorly differentiated. This case report discusses the clinical, macroscopic, microscopic and immunohistochemical features of oral histiocytic sarcoma in a cat with mandibular invasion and submandibular lymph node metastasis.

Relevance and novel information

Feline primary oral histiocytic sarcoma is rare and tumor behavior and prognosis are unclear. This report broadens the immunohistochemical features of the tumor and recognizes mandibular invasion and submandibular lymph node metastasis.

Periarticular histiocytic sarcoma with heart metastasis in a cat

A 4-year-old intact female domestic short-haired cat was referred for recommendations about adjuvant medical treatment 1 month after left forelimb amputation due to periarticular histiocytic sarcoma (HS). At presentation, physical abnormalities were limited to enlarged ipsilateral superficial cervical and axillary lymph nodes. Routine blood analysis, abdominal ultrasound, and thoracic radiology were unremarkable. The cat initially received lomustine without any adverse events. Four weeks later, the cat developed severe acute respiratory distress. Results of thoracic radiographs and transthoracic echocardiographic analysis were suggestive of pulmonary and heart metastasis. Due to the cat's poor clinical condition and prognosis, the owner elected euthanasia, and a necropsy was performed. Based on gross pathology, histopathology, and immunohistochemistry, an HS with nodal, renal, pulmonary, and heart (right auricular and right ventricular) metastases was diagnosed. This case represents the first description of HS with a heart metastasis in a cat, providing further insight into the clinical course and metastatic behavior of this rare malignant neoplasm. Clinicians should be aware of this site of metastasis and consider HS in the list of differential diagnoses for secondary heart tumors in cats.

Tracheal Squamous Cell Carcinoma Treated with Tracheal Resection and Anastomosis in a Cat

A 10-year-old male castrated domestic shorthair cat presented for a suspected tracheal mass. Radiographs confirmed an intraluminal tracheal mass. Tracheal resection and anastomosis of 5 tracheal rings was performed with minimal, mild intraoperative complications and no postoperative complications. Histopathology of the tracheal mass revealed a diagnosis of squamous cell carcinoma (SCC) with incomplete margins both cranially and caudally. Further treatment, including surgical revision, radiation therapy, or chemotherapy, was recommended. At the time of publication, no further treatment has been initiated, and a scheduled consultation with the oncologist has been canceled. The cat is doing well at home with no reported signs of recurrence 120 days postoperatively. This is the first report of a cat with a tracheal SCC to be treated with a tracheal resection and anastomosis and only the third feline tracheal SCC to be treated in the veterinary literature.

Oral histiocytic sarcoma in a cat

CASE SUMMARY

A 15-year-old neutered male domestic shorthair cat presented with a 4-week history of dysphonia and reluctance to chew hard food. Oral examination revealed a mass lesion on the caudal soft palate. Biopsy was performed and histopathology with immunohistochemistry was most consistent with histiocytic sarcoma. CT of the head identified a discrete, left-sided, soft tissue mass lesion cranial to the tonsil with bilaterally symmetrical regional lymph nodes. CT of the thorax was unremarkable. Surgical removal achieved cytoreduction but not complete removal. Adjuvant chemotherapy with lomustine 10 mg (30 mg/m2) was initiated. The patient developed suspected pancreatitis 2-3 weeks postoperatively, so further chemotherapy treatment was discontinued, but supportive treatment with pain relief and appetite stimulants was provided. Three months postoperatively, the patient developed recurrent dysphonia, and oral examination revealed a suspicion of local recurrence. Confirmation of diagnosis (cytopathology or histopathology) was not obtained. Supportive treatment to maintain a good quality of life was continued and the patient was euthanased 6 months after diagnosis owing to progressive disease.

RELEVANCE AND NOVEL INFORMATION

Only a few reports have been published describing histiocytic diseases of cats. To our knowledge, this is the first report of a feline histiocytic sarcoma of the oral cavity. Therefore, histiocytic sarcoma should be considered as a differential diagnosis in feline patients with an oral mass, especially if histopathology suggests a pleomorphic and poorly differentiated sarcoma. Immunohistochemistry for the confirmation of cell line origin would be strongly recommended.

Feline progressive histiocytosis: a retrospective investigation of 26 cases and preliminary study of Ki67 as a prognostic marker

Feline progressive histiocytosis (FPH) is an uncommon and infrequently reported cutaneous histiocytic proliferative disorder, whose clinical presentation is solitary or multiple cutaneous nodules and papules, with late-course internal metastasis. We describe herein the clinical, epidemiologic, histologic, and immunohistochemical features of this entity, and document the outcome of FPH based on a retrospective study of 26 cases. Female and male cats were affected equally. Lesions were evident either as solitary (16 of 26 cases) or multiple (10 of 26 cases) nonpruritic and alopecic nodules or plaques, preferentially located on the legs and extremities (73%). Follow-up was complete for 19 cats, and ranged from 41 to 1,449 d. Nine died of FPH with a median overall survival of 96 d (range: 41-238 d). The disease recurred in 14 cats after surgical excision of the nodules, and the median disease-free survival was 175 d (range: 21-1,449 d). Five of the 26 cats were alive at the end of the study, and 4 had no progression of the disease. Histologically, lesions were characterized by poorly circumscribed, unencapsulated histiocytic infiltration of dermis and subcutis. Epitheliotropism was observed in 11 (42%) cats. Atypical histiocytes diffusely and consistently expressed MHC II, CD18, and Iba1. Statistically significant higher E-cadherin expression was observed in epitheliotropic cases compared to non-epitheliotropic cases. A negative correlation between overall survival and proliferation index was evident, thus suggesting Ki67 as a promising prognostic marker.

Invasive tracheal neoplasia in eight cats: descriptive cases and review of the current literature

Case series summary

This case series describes eight cases of invasive tracheal neoplasia that were recognized between the years 1989 and 2014 from a single tertiary referral hospital. This is a disproportionately high number of cases compared with the total number of reports in the current literature.

Relevance and novel information

Invasive tracheal neoplasia is uncommonly diagnosed in domestic cats. Feline tracheal tumors mimic other upper respiratory diseases making diagnosis challenging. Prognosis is guarded to grave, with most cats surviving less than 1 month after beginning treatment. Severe respiratory distress in cats often warrants humane euthanasia. Appropriate clinical suspicion and awareness can expedite diagnoses leading to prolonged survival rates with appropriate treatments. This case series represents the largest number of feline tracheal tumors reported and also describes the first unique histological presentation of what the authors believe to be a poorly differentiated tracheal carcinoma.

Primary nasal histiocytic sarcoma of macrophage-myeloid cell type in a cat

A 16-year-old neutered male Burmese cat was presented with a locally invasive nasal mass. The cytological and histological findings on incisional biopsy of this mass were suggestive of histiocytic sarcoma. Tumour cells expressed CD18, major histocompatibility complex class II, lysozyme and alpha-naphthyl acetate esterase; and lacked expression of CD3, CD79a, CD1a, CD1b, calprotectin, CD11c and E-cadherin. These findings are consistent with a myeloid-macrophage lineage. Metastasis to the bone marrow was present on necropsy examination. Histiocytic sarcoma should be considered in cats presented with primary round cell neoplasia of the nasal cavity.

Amputation for histiocytic sarcoma in a cat

A 9-year-old spayed female domestic shorthair cat presented with a skin lesion of the left tarsus. The lesion was biopsied and, based on the microscopic appearance and immunohistochemical characteristics, histiocytic sarcoma was diagnosed. Amputation was performed with improved demeanor seen postoperatively. However, between 44 and 60 days following the surgery, relapse of skin lesions appeared in multiple locations, including at the previous amputation site, and euthanasia was elected. This is the first report of a histiocytic sarcoma treated with amputation in a cat.

Radiographic measurements of the trachea in domestic shorthair and Persian cats

Tracheal diameter can be assessed from a thoracic radiograph, with assessment of tracheal diameter in dogs based on ratios between tracheal diameter and a skeletal measurement. Reference intervals are not, however, available for the cat. Tracheal narrowing may cause significant clinical problems, although tracheal hypoplasia in dogs may be clinically silent, and is rarely reported in cats (both mesati- and brachycephalic). The tracheal diameter and trachea:thoracic inlet and trachea:rib ratios were calculated for populations of domestic shorthair (DSH) (n = 68) and Persian (n = 40) cats. This gave reference intervals for radiographic tracheal measurements in these breeds. It is proposed that the tracheal diameter in a normal DSH cat should be 18% of the diameter of the thoracic inlet, and compared to 20% in Persian cats.