Page 1873 - Cote clinical veterinary advisor dogs and cats 4th

940 Squamous Cell Carcinoma

• Oral ○ Cat: locally invasive with digital (P3) to be positive (except tonsillar SCC) but an
easy test with prognostic value
○ Difficulty eating, reluctance to eat, destruction; usually, metastatic lesions • Three-view thoracic radiographs to assess for
VetBooks.ir pawing at mouth, facial mass, oral mass, • Oral • Fine-needle aspiration (FNA) and cytologic
drooling, halitosis, bloody oral discharge,
from a pulmonary tumor. Lymph node
involvement not documented.
metastasis; usually negative
loose teeth, or weight loss. Tonsillar
SCC: presenting complaint may be
sible to obtain the samples on animal that
sive with a low metastatic rate (5%-10%
“lumps under jaw” from metastasis to ○ Gingival and sublingual SCC: locally inva- exam of the primary mass; it may be pos-
the mandibular lymph nodes, with no regional lymph nodes, 3% lung) is awake, but if sedation is needed, plan to
other clinical signs. ○ Tonsillar SCC: invasive and highly biopsy as well.
metastatic (98% regional lymph nodes, ○ Cytologic exam can provide a definitive
PHYSICAL EXAM FINDINGS 63% lung) diagnosis, but severe inflammation can
• Planum and pinna: lesion may be proliferative hamper interpretation of malignancy,
or erosive; mass, crusting, and/or ulcerative DIAGNOSIS necessitating a biopsy.
lesion may be present. Regional lymph node Cats:
may be enlarged. Diagnostic Overview • Planum and aural (see Dog above): hypercal-
• Aural, external ear canal: otic exam shows The diagnosis of SCC is suspected based on cemia rarely seen as paraneoplastic syndrome
raised irregular mass, often ulcerated. Palpa- signalment, physical exam, at times cytologic in ear canal SCC
tion of vertical ear canal may reveal large analysis, but is confirmed by histopathologic • Digital: three-view thoracic radiographs
mass invading the area in late-stage cases. evaluation from incisional/excisional biopsy almost always reveal lung neoplasia; usually
• Digital sample. solitary mass but may be multiple. FNA
○ Dog: painful swollen digit with an and cytologic exam of the digital mass can
abnormal or absent claw ± ulceration. Differential Diagnosis provide a definitive diagnosis, but at times
Regional lymph node may be enlarged. Planum: extreme inflammation of the tumor can make
○ Cat: swollen digit, ulcerated skin with • Fungal lesion (particularly Cryptococcus in interpretation of the epithelial cells difficult.
purulent discharge; constant exsheath- cats) These cells, although usually pulmonary
ment, deviation, or loss of nail; 80% of • Other neoplasms: cutaneous lymphoma, adenocarcinoma in origin, may have some
cats with digital carcinoma metastasis mast cell tumor, fibrosarcoma, melanoma, squamous differentiation. FNA of the lung
from a primary lung tumor present with eosinophilic granuloma mass can confirm a lung tumor if the digit
multiple digits involved. The less common • Immune-mediated dermatopathy lesion is nondiagnostic.
primary SCC of the digit usually involves Aural: • Oral: mandibular lymph node FNA and
only one digit with possible local extension • Canal: severe hyperplasia in dogs with chronic cytologic exam to assess for metastasis in
into an adjacent digit. otitis, ceruminous gland adenocarcinoma, all cases. Hypercalcemia may be seen as a
• Oral adenoma, papilloma, polyp, plasmacytoma, paraneoplastic syndrome in some cats with
○ Gingival SCC: swelling or raised mass basal cell tumor, melanoma, granuloma oral SCC. Three-view thoracic radiographs
along gingival margin may be irregular, • Pinna: consider trauma, frostbite, insect bites to assess for metastasis
ulcerated. Cats can have normal gingiva, (see Planum above).
with the tumor affecting the mandible/ Digital: Advanced or Confirmatory Testing
maxilla leading to bone mass. • Dog: melanoma, mast cell tumor, soft-tissue • Incisional or excisional biopsy of the primary
○ Tonsillar SCC: enlarged mandibular lymph sarcoma, osteomyelitis, paronychia mass for histopathologic diagnosis
nodes and enlarged irregular tonsils may • Cat: usually metastatic lung tumor; bacterial • Radiographs, CT scan of lesion to assess
be seen. Tonsillar enlargement is usually paronychia; other primary tumors much less tumor extent and bone involvement and to
unilateral. likely plan surgery or radiation therapy
○ Sublingual SCC: irregular mass under Oral:
tongue; in dogs, lingual SCC often • Gingival mass in a dog: melanoma, fibro- TREATMENT
involves the ventral aspect of the tongue sarcoma, acanthomatous ameloblastoma
with limited dorsal involvement noted on (acanthomatous epulis). Less likely are Treatment Overview
physical exam. osteosarcoma, plasma cell tumor, tooth root Excision of primary tumor with wide margins
• Multicentric SCC in situ (MSCCIS, Bowen’s abscess, fungal disease, and other primary is often curative, as indicated by low metastatic
disease, bowenoid in situ carcinoma [BISC]) tumors. rates for most primary locations except the
is an uncommon disease reported mainly • Gingival mass in a cat: fibrosarcoma, dental tonsil. Due to location and extent of lesion
in cats. Lesions are multifocal; occur most disease. Less likely are melanoma and other in many cases, however, wide excision may be
commonly over the head, neck, dorsal thorax, primary tumors. difficult or impossible.
abdomen, and proximal limbs. Lesions found • Tonsillar mass in a dog: lymphoma. Less
in haired and darkly pigmented skin; not likely is bacterial or fungal infection. Acute General Treatment
solar induced. • Sublingual mass in a cat: foreign body, fungal Wide surgical resection; if margins are not
infection, other neoplasia complete on histologic evaluation, irradiation
Etiology and Pathophysiology • Lingual mass in a dog: melanoma, hemangio- is effective for microscopic disease.
• Planum and pinna: may begin as actinic sarcoma, fibrosarcoma, granular cell tumor, • Planum
keratosis and become locally invasive; low plasma cell tumor, papilloma ○ Dog: excising the premaxilla along with
metastatic rate, possible association in some the planum in cases with very large masses
cases with papillomavirus Initial Database may provide better cosmesis.
• Aural, external ear canal: locally invasive, more Dog, all sites: ○ Cat: excision is an excellent option if the
aggressive in cats than dogs; low metastatic • CBC, serum biochemistry profile, urinalysis; tumor is not too extensive along the bridge
rate (about 5%-15% local lymph nodes) usually unremarkable of the nose or does not involve the lip or
• Digital • Aspirate and cytologic exam from regional surrounding skin. Irradiation, photody-
○ Dog: locally invasive with digital (P3) lymph nodes (mandibular, also superficial namic therapy, cryotherapy, intralesional
bony destruction, low metastatic rate cervical nodes [prescapular] for aural masses) chemotherapy (intralesional carboplatin:
(5%-20% lymph node or pulmonary) to assess for metastasis in all cases; unlikely complete remission for > 9 months in 6/6

www.ExpertConsult.com