BRIEF COMMUNICATIONS COMMUNICATIONS BREVES

JJ

Cutaneous metastases of a mammary carcinomain a llama

Teri L. Leichner, Oliver Turner, Gary L. Mason, George M. Barrington

Abstract- An 8-year-old, female llama was evaluated for nonhealing, ulcerative, cutaneous lesions,which also involved the mammary gland. Biopsies of the lesions distant from and within themammary gland area revealed an aggressive carcinoma. The tumor was confirmed at necropsy to bea mammary gland adenocarcinoma with cutaneous metastasis.

Resume - Metastases cutanees d'un carcinome mammaire chez un lama. Un lama femellede 8 ans a ete evalue pour des lesions cutanees ulceratives qui ne guerissaient pas et qui incluaientegalement la glande mammaire. Des biopsies provenant des lesions eloignees ainsi que de laglande mammaire ont revele un carcinome agressif. La necropsie a confirme la presence d'unadenocarcinome de la glande mammaire avec metastases cutanees.

(Traduit par Docteur Andre Blouin)Can Vet J 2001;42:204-206

n 8-year-old, intact female llama (Llama glama)tAlwas presented to the Colorado State UniversityVeterinary Teaching Hospital (CSU-VTH) for a pri-mary complaint of diffuse crusting and scale locatedalong the dorsal lumbosacral area. One month earlier, thellama had been examined by the ambulatory servicefor dry, crusty patches of skin at the same location. Atthat time, recommended treatments were daily cleansingof the area with dilute povidone-iodine scrubs andapplication of tincture of iodine. The lesions did notresolve with the initial treatment and the llama wasreferred to the CSU-VTH for additional diagnosticprocedures.On physical examination, an 18- X 24-cm, malodor-

ous, ulcerated lesion was observed in the inguinal regionover the mammary gland. The mammary gland wasindurated. Multiple, variably sized, depressed, ulcerated,circular lesions extending along the dorsal thoracic to thesacral area were also apparent. A 3- X 5-cm lesion,located just lateral to the right ischium, was covered with

Department of Veterinary Clinical Sciences (Leichner,Barrington), Department of Pathology (Turner, Mason),College of Veterinary Medicine and Biomedical Sciences,Colorado State University, Fort Collins, Colorado 80523USA.

Address correspondence to Dr. Teri Leichner.

Dr. Leichner's current address is Virginia-Maryland RegionalCollege of Veterinary Medicine, Phase II, Duckpond Drive,Virginia Polytechnic Institute and State University, Blacksburg,Virginia 24061-0442 USA.

Reprints will not be available.

fragile skin that was readily excoriated (Figure IA).The proximal part of the right hind limb was edematousand pitted on pressure; the right popliteal lymph node wasapproximately twice the normal size. No other abnor-malities were noted on physical examination. Differentialdiagnoses for the cutaneous lesions included severebacterial pyoderma, pemphigus, vasculitis, cutaneous der-matophilosis, and cutaneous neoplasia. Differentialdiagnoses for the mammary gland included the afore-mentioned differentials plus chronic mastitis and primarymammary neoplasia.A complete blood cell count (CBC), serum bio-

chemical analysis, and thoraco- and abdominocentesiswere performed. The CBC revealed mild hyperfib-rinogenemia (14.75 pmol/L; reference range, 2.95 to11.7 pmol/L). Serum biochemical analysis revealedhypoglycemia (4.28 mmol/L; reference range, 5.0 to7.78 mmol/L), hypoproteinemia (49 g/L; referencerange, 55 to 70 g/L), hypoalbuminemia (26 g/L; referencerange, 35 to 44 g/L), and hypokalemia (4.0 mmol/L; ref-erence range, 4.3 to 5.6 mmol/L). These changes wereconsistent with a partially anorectic animal with aninflammatory and protein-losing disease. Abdominocen-tesis and thoracocentesis yielded hazy, pale yellowfluid with a total protein of 23 g/L and 21 g/L, and500 cells/pL and 400 cells/pL, respectively. Cytologicalevaluation of the abdominal fluid revealed many largemononuclear and fewer multinucleate cells that dis-played marked anisocytosis and anisokaryosis. Thesecells had a deeply basophilic cytoplasm and single tomultiple nuclei with large, irregular nucleoli. Nuclearmolding and epithelial junctions were noted betweensome of the cells, and a few of the cells had large, clearcytoplasmic vacuoles. Mitotic figures were present in

Can Vct J Volume 42, March 2001204

qo & 1 e WAX 1-l

Figure 1. A) Cutaneous lesion, right ischium. Focal ulcerative dermatitis typical of all cutaneous lesions. B) Cutaneouslesion. Note extensive hypodermal invasion by multilobulated, densely cellular mass; hematoxylin and eosin stain; bar = 1 mm.C) Mammary gland. Note pleomorphic cellular population with marked anisocytosis and anisokaryosis; hematoxylin andeosin stain; bar = 1 mm. D) Mammary gland, longitudinal section. Diffuse infiltration by carcinoma.

moderate numbers. The morphology of the cells obtainedfrom the thoracic cavity were similar. These findingswere consistent with anaplastic carcinoma.The llama was anesthetized with ketamine hydrochlo-

ride (4.4 mg/kg body weight [BW], IM), xylazinehydrochloride (0.4 mg/kg BW, IM), and butorphenol(0.04 mg/kg BW, IM). Nasal oxygen insufflation at4 L/min was provided. Multiple punch biopsies (5 mmdiameter) were obtained from the skin and tissue sur-rounding and including the mammary gland and dorsallumbosacral areas. All biopsies were submitted for bac-teriologic culture and histopathologic examination. Noaerobes were isolated. Histopathologic findings were sim-ilar at all sites and revealed a highly anaplastic, infil-trative mass that frequently replaced large areas of nor-mal dermal and hypodermal tissue (Figure 1B). Somesections were ulcerated and coated by an adherentserocellular crust. The mass was organized as lobulesarranged into sublobules of varying size composed ofirregular packets and cords of cells that, rarely, formedcrude acini. The entire tissue was dissected by a densefibrous stroma. Cells were irregular in outline, usuallyround to oval, and from 10 to 200 pm in diameter.Prominent nucleoli, bizarre multinucleate giant cells,and abnormal mitotic figures were present (Figure IC).

A diagnosis of anaplastic mammary carcinoma wasmade.

Thoracic and abdominal radiographs were taken in anattempt to document the extent of the neoplastic process.Thoracic radiographs revealed a diffuse, miliary nodu-lar pattern throughout all lung fields consistent withpulmonary metastatic disease. Other differentialdiagnoses included fungal pneumonia or lymphoma.Abdominal radiographs appeared normal.

Because of the evidence of widespread metastasisand poor prognosis for survival, euthanasia was elected.At necropsy, no normal mammary tissue could be seen.There are normally 4 teats; however only 2 small teatswere present, 1 in each of the cranial quadrants. The nor-mal anatomic separation of the mammary gland into8 compartments was not apparent; instead, the entiregland was replaced by a firm, tan mass (Figure 1D). Thismass extended 10 cm craniad in a subcutaneous planefrom the normal cranioventral limit of the mammarygland. The right inguinal, prefemoral, and popliteallymph nodes were enlarged to approximately twice thenormal size. On the cut surface, all affected sites had dif-fuse infiltration by tissue grossly similar to that in themammary gland. There was extensive edema withinthe subcutaneous fascia of the proximal part of the

Can Vet J Volume 42, March 2001

11

I".

.I

.j I

,. i. .

I1.1 I

a ."

.0

41,

4

205

right hind leg. Approximately 3 L of clear, pale straw-colored fluid with fibrin strands was present in both thepleural and peritoneal cavities. There were multifocal tocoalescing pale, tan, firm, 0.5- tol.0-mm nodules through-out all lung lobes. Mediastinal and bronchial lymphnodes were enlarged to approximately twice the normalsize and were infiltrated by the same abnormal tissue.Multifocal to coalescing 0.5- to 2.0-cm diameter, raised,pale, tan, fibrous nodules were also present on thepleural surface of the intercostal muscles, colonic serosa,peritoneal surface of the dorsum of the pelvic inlet,omentum, mesentery, and capsular surface of the liver.

Results of the histologic examination of tissues col-lected at necropsy were similar to those from earlier biop-sies and confirmed that the neoplasm originated from themammary gland. Metastasis was confirmed in all abnor-mal tissues seen at gross examination with, in addi-tion, microscopic metastases to adrenal glands. Stronglypositive immunohistochemical staining within mammarytissue and skin lesions for the intracytoplasmic inter-mediate filament, cytokeratin, and negative stainingfor vimentin, confirmed that the tumor was of epithelialorigin (NEXES automated processor with anti-pan-keratin (mouse IgG) and anti-vimentin (mouse IgG)antibodies; Ventana Medical Systems, Tucson, Arizona,USA). Transmission electron microscopy of mammarytissue was also performed. Tissues were diced into 1-mmcubes and fixed by immersion in 2.5% glutaraldehyde.These were then post fixed in osmium tetroxide, dehy-drated in a graded ethanol series, cleared in propyleneoxide, and embedded in Polarbed 812. Thin sections werestained with toluidine blue for orientation. Ultrathinsections were stained with uranyl acetate and lead citrate.

Neoplastic cells had irregular cell borders with elab-oration of microvillus-like surface projections, dilatedmitochondria, desmosomes, and dense bundles of inter-mediate filaments. These findings confirmed that theirorigin was epithelial. Immunohistochemical stainingfor estrogen receptors (Estrogen receptor Ab- 13 (cloneTE 11 .5d1 1); Lab Vision Corp-Neomarkers, Fremont,California, USA) was performed and revealed mild tomoderate mixed positive cytoplasmic and nuclearstaining in approximately 30% of the neoplastic cells.Staining in human mammary adenocarcinoma andnormal alpaca mammary tissues with the same anti-body was nuclear and cytoplasmic, respectively. A fewcrude acini were observed in all sections of tumorexamined, suggesting adenocarcinoma; however, thepredominant pattern of tumor growth was that of asolid carcinoma. The final diagnosis was a scirrhousanaplastic mammary carcinoma with extensive multi-system metastasis.Mammary epithelial neoplasias have been described

in horses, goats, swine, cats, dogs, buffalo, rodents,and llamas (1-2). Common sites for metastasis of mam-mary neoplasia in mammalian species include regionallymph nodes, liver, lungs, pleura, spleen, and eye. In cats,even with extensive surgical removal, tumor size isdirectly related to disease-free time but not to survival(3,4). In this llama, the extent of the metastasis precludedany attempts at therapy.

Reports of neoplasia in New World camelids areuncommon (2,5). Mammary adenocarcinoma is only

mentioned briefly; it was a mammary tumor of ductal ori-gin (2). Radical mastectomy was performed; however,1 y later the tumor recurred in the mammary region. Atnecropsy, metastasis to the sublumbar lymph nodeswas observed. There are significant differences in thenature of the tumor described in this earlier report and theone reported here. To the best of our knowledge, such alocally aggressive, ulcerative, and highly metastaticmammary adenocarcinoma has not been described pre-viously in a llama.The pathogenesis of adenocarcinomas is unknown

for llamas, but estrogens and progesterones may influ-ence tumor growth and progression. Documentation ofestrogen and progesterone receptors in human breast can-cer (6) and in canine mammary neoplasms (7,8) supportshormonal effects, while only progesterone receptorshave been identified in cats (9). A B-type RNA virus isoften associated with mammary neoplasia in mice (1).The degree of positive nuclear staining was interesting,but no conclusions can be drawn from the evaluation ofthis single case.To our knowledge, cutaneous metastasis of a pri-

mary mammary gland adenocarcinoma has not beenreported in the llama. Cutaneous metastasis of a mam-mary adenocarcinoma, representing possibly local lym-phatic extension of the tumor, has been reported previ-ously in a cat, where it resembled eosinophilic plaques(10). Occlusion of lymphatic vessels with subsequent ret-rograde cutaneous relocation of tumor cells may play arole in the development of these lesions. Mammaryadenocarcinomas are usually locally invasive early,but rapidly metastasize to other areas of the body. Evenwith aggressive therapy, the prognosis for affected ani-mals is guarded at best. cv,

References1. Theilen GH, Madewell BR. Tumors of the mammary gland. In:

Theilen GH, Madewell BR, eds. Veterinary Cancer Medicine,1979:192-203.

2. Smith JA. Noninfectious, metabolic, toxic and neoplastic dis-eases of camelids. In: Johnson LW, ed. Vet Clin North Am FoodAnim Pract 1989:138-141.

3. Hahn KA, Adams WH. Feline mammary neoplasia: biologicalbehavior, diagnosis, and treatment alternatives. Feline Pract1997;25(2):5-1 1.

4. Castagnaro M, Casalone C, Bozzetta E, De Maria R, Biolatti B,Caramelli M. Tumour grading and the one-year post surgicalprognosis in feline mammary carcinomas. J Comp Pathol1998;1 19:263-275.

5. Rogers K, Barrington GM, Parish SM. Squamous cell carcinomaoriginating from a cutaneous scar in a llama. Can Vet J 1997;38: 1-2.

6. McGuire WL. An update on estrogen and progesterone receptorsfor primary and advanced breast cancer. In: lacobelli S, KingRJB, Linder HR, Lippman ME, eds. Hormones and Cancer(Progress Cancer Research) 1980; 14:337-344.

7. Monson KR, Malbica JO, Hubben K. Determination of estrogenreceptors in canine mammary tumors. Am J Vet Res 1977;38:1937-1939.

8. Nelson LW, Carlton WW, Weikel JH. Canine mammary neo-plasms and progestogens. J Am Med Assoc 1972;219:1601-1606.

9. Johnston SD, Hayden DW, Kiang DT, Handschin B, JohnsonKH. Progesterone receptors in feline mammary adenocarcino-mas. Am J Vet Res 1984;45:379-382.

10. White SD, Carpenter JL, Rappaport J, Swartout M. Cutaneousmetastases of a mammary adenocarcinoma resembling eosinophilicplaques in a cat. Feline Pract 1985;15:27-29.

206 Can Vet J Volume 42, March 2001