- Email: [email protected]
Fibromyxoma in a flower horn fish (hybrid cichlid)
Author’s Accepted Manuscript FIBROMYXOMA IN A FLOWER HORN FISH (HYBRID CICHLID) Sara Shokrpoor, Farhang Sasani, Rahmati-Holasoo, Ashkan Zargar
Hooman
www.sasjournal.com
PII: DOI: Reference:
S1557-5063(17)30139-8 http://dx.doi.org/10.1053/j.jepm.2017.05.005 JEPM731
To appear in: Journal of Exotic Pet Medicine Cite this article as: Sara Shokrpoor, Farhang Sasani, Hooman Rahmati-Holasoo and Ashkan Zargar, FIBROMYXOMA IN A FLOWER HORN FISH (HYBRID CICHLID), Journal of Exotic Pet Medicine, http://dx.doi.org/10.1053/j.jepm.2017.05.005 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Case Report
Fibromyxoma in a Flower Horn Fish (Hybrid Cichlid) Sara Shokrpoor, DVM, DVSc, Farhang Sasani, DVM, DVSc, Hooman Rahmati-Holasoo, DVM, PhD Ashkan Zargar, DVM, PhD From the Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran (Shokrpoor, Sasani), Department of Aquatic Animal Health, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran (Rahmati-Holasoo, Zargar). Address correspondence to Sara Shokrapoor, DVM, DVSc, Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, P.O. Box 141556453, Tehran, Iran. E-mail address: [email protected]
Abstract A 3-year-old male flower horn fish with a mass on the head protuberance was referred to the Ornamental Fish Clinic, Faculty of Veterinary Medicine, University of Tehran. On gross examination, the mass was approximately 4×15×25 mm in size. The fish was anaesthetized in 100 ppm PI222 (Pars Imen Daru, Iran). The mass was removed surgically and the wound repair was post operatively monitored in the Ornamental Fish Clinic for 40 days. Tissue samples of the mass were fixed in 10% neutral buffered formalin, sectioned and stained with haematoxylin and eosin (H&E), Periodic Acid-Schiff (PAS) and
Masson’s
trichrome.
Microscopically,
as
a
consequence
of
the
concomitant presence of collagenous areas infiltrating myxoid areas, the neoplasm was classified as a fibromyxoma. Key words: Fibromyxoma; head protuberance; flower horn fish, neoplasm
A male flower horn fish (hybrid cichlid) with a mass on the head protuberance was referred to the Ornamental Fish Clinic, Faculty of Veterinary Medicine, University of Tehran (Fig. 1A). Based on owner information, the fish was 3-years-old and within the previous 6-month period of time the mass had become evident and grew larger. The flower horn fish’s behavior and appetite were considered normal. No parasite or ova were observed in wet smears of skin, gills, and feces. On gross examination, the fish measured 23 cm total length and the head mass was approximately 4×15×25 mm in size. The colored mass also exhibited an umbilicated center (Fig. 1). Water parameters were within normal range for this species of fish (29 °C, pH 7.2 and O2 7.9 mg/L) when the fish was first presented to the Ornamental Fish Clinic. The fish was anesthetized in 100 ppm PI222 (Pars Imen Daru, Iran) (PI222 is an herbal medicine and contains "eugenol, carvacrol, eugenol acetate and some other effective substances" as the active ingredients). The mass was surgically removed in a 5-minute procedure for diagnostic histopathological evaluation. During the surgical procedure the gills were periodically hydrated. Postoperatively, oxytetracycline (25 mg/kg, intramuscularly, Oxyvet®) was provided and then 10 mg/L oxytetracycline was added to the tank water and retreated on day 3 after 50% water change. After initially treatment, 50% of tank water was changed on days 6 and 9. Following the excision of the mass, the wound repair was monitored for 40 days in clinic (Fig. 2AH). The remaining parts of the mass (Fig. 2A,B,C) were excised completely on day 9 following the first surgical procedure. The fish was sedated each time the fish was photographed. The cut surface of the mass was soft with trabecular structures and gelatinous in consistency. Tissue samples of the mass were fixed in 10% neutral buffered formalin and routinely processed, dehydrated and embedded in paraffin wax, sectioned at 5 µm in thickness (Rotary Microtome RM2145; Leica) and stained
with hematoxylin and eosin (H&E). The mass sections were also stained with Periodic Acid-Schiff reaction (PAS) and Masson’s trichrome. Microscopically, the mass was capsulated and myxoid areas were characterized by stellate-to-reticular cells distributed in a mucinous stroma containing few tiny blood vessels that was partitioned by collagenous connective tissue septae (Fig. 3A,B,C). The myxoid cells were scattered appearing singly or in small clusters. There was no evidence of mitotic figures, but aberrant, bizarre and pyknotic nuclei were seen (Fig. 3D). The hypocellular mass showed neither hemorrhage nor necrosis. Myxoid cells displayed a PAS positive cytoplasm and round to oval, pale nuclei (Fig. 3E). The presence of stellate, reticular and PAS positive cells lying in a mucoid matrix are diagnostic of myxoma. Collagenous areas appeared rich in convoluted, collagenous fibers and in connective tissue cells, that included spindle-shaped fibroblast, in appearance, cells. Collagenous fibers stained also positive for Masson’s trichrome (Fig. 3F). Due to the concomitant presence of collagenous areas infiltrating myxoid areas, the neoplasm was classified as a fibromyxoma. Based on owner information, no new growth of the mass has been observed 8 months following the surgical procedures.
DISCUSSION The flower horn fish belongs to the Cichlid family. This species was believed to be a hybrid between the Midas cichlid (Amphilophus citrinellus) and three spot cichlid (Cichlasoma trimaculatum) which was first produced in Malaysia.1 It is also believed that this fish has emerged through selective cross-breeding of three spot cichlid (Cichlasoma trimaculatum), guayas cichlid (Cichlasoma festae) and Jingang Blood
Parrot (hybrid cichlid) in 1996.2,3,4,5 This fish is becoming increasingly popular as a pet, especially in South-East Asia and Iran.2,3,4,6 Fibromas are benign neoplasms of fibrocytes with abundant collagenous stroma. Myxomas are tumors of fibroblast origin distinguished by their abundant myxoid matrix, rich in mucopolysaccharides.7 The concomitant presence of collagenous areas delimiting and infiltrating myxoid areas lead the authors to classify the mass as a fibromyxoma.8 Fibromas have been described in electric catfish (Malapterurus electricus)9, southern flounder (Paralichthys lethostigma) and the hardhead sea catfish (Arius felis)10, flathead grey mullet (Mugil cephalus)11, redband parrotfish (Sparisoma aurofrenatum)12, common carp (Cyprinus carpio13, and goldfish (Carassius auratus)14. Myxomas have been reported in ayu sweetfish (Plecoglossus altivelis altivelis)15, yellowtail amberjack (Seriola lalandi)16, European eel (Anguilla anguilla)17, and Blackfin sea catfish (Arius jella)18. Fibromyxoma has rarely been diagnosed in fish only having been described in a tench (Tinca tinca)8. The presence of myxoid areas is a frequent occurrence in many mesenchymal neoplasms of domestic animals and humans.19 Myxomas have been reported in many species of animals including horses, cats, dogs, cattle and sheep.20,21,22,23,24 Myxomas have been also described in fish,15,16,17,18 but their occurrence is rare compared to fibromas.8 Microscopically, myxomas have low cellularity and rare mitoses, but increases in cellular density and mitoses warrant the diagnosis of myxosarcoma.7 However, no hypercellularity and mitoses were identified in the present case. Myxoma can be diagnosed only on the basis of tumor histopathology, because the loose tissue does not give clear and reliable
immunohistochemistry
results.17
The
intermediate
form
of
myxomas
(e.g.,
fibromyxoma) has been only reported in tench, Tinea tinea L.8 which had histological findings similar to the fibromyxoma diagnosed in the flower horn fish described in this report. Myxomas generally are considered to be spontaneous and self limiting16 and surgical excision is considered the treatment of choice for myxomas, fibromas, and intermediate forms7, which was also performed successfully in the present case. Fibromas and myxomas are usually diagnosed in adult or aged animals7 similar to fibromyxoma in the flower horn fish. Predisposing factors such as carcinogenic compounds, viruses, irritants, oncogenes, and parasites have all been reported in teleosts and should be considered potential sources for tumor induction in tropical fish.25 However in this report, no predisposing factors were observed and the underlying cause of the flower horn fish tumor remains unknown.
ACKNOWLEDGEMENTS Mr. Mehran Ahmadpour is thanked for assisting with the histopathological sections and figures.
REFERENCES 1. Shin SP, Jee H, Han JE, et al: Occurrence of Goiter in Flowerhorn Cichlid (Family: Cichlidae) and its Effect on Liver. J Vet clinic 27:202-204, 2010 2. Lin CC, Hung SW, Tu CY, et al: Spontaneous stomach lymphoma and liver metastases in flower horn fish, hybrid cichlid. Bull Eur Assoc Fish Pathol 28:115-120, 2008
3. Rahmati-Holasoo H, Hobbenaghi R, Tukmechi A, et al: Lymphocystis in a flower horn fish. Comp Clin Pathol 19:433-435, 2010 4. Rahmati-Holasoo H, Ebrahimzadeh Mousavi H, Vajhi A, et al: Polycystic liver in flower horn fish, hybrid cichlid. J Fish Dis 38:325-328, 2015a 5. Rahmati-Holasoo H, Masoudifard M, Ebrahimzadeh Mousavi H, et al: Cystic lesions in the kidney of flower horn fish, hybrid cichlid. J Fish Dis 38:833-838, 2015b 6. Rahmati-Holasoo H, Shokrpoor S, Tavakkoli A, et al: Liposarcoma or invasive lipomatosis in flower horn fish, hybrid cichlid: clinical, radiological, ultrasonographical and histopathological study. J Fish Dis 39:309-315, 2016 7. Goldschmidt MH, Hendrick MJ: Tumors of the skin and soft tissues, in Meuten DJ (ed): Tumors in Domestic Animals (ed 4). Ames, Iowa, Lawa State Press, pp 84-92, 2002 8. Manera M, Biavati S: A fibromyxoma in a tench, Tinca tinca L. J Fish Dis 18:627-630, 1995 9. Stolk A: Tumours of fishes. XIII. Multiple fibromas of the skin in the malapterurid Malapterurus electricus. Proc Kon Ned Akad Wetensch Ser C Biol Med Sci 60:41-52, 1957 10. Overstreet RM, Edwards RH: Mesenchymal tumors of some estuarine fishes of the northern Gulf of Mexico. II. Subcutaneous fibromas in the southern flounder, Paralichthys lethostigma, and the sea catfish, Arius felis. Bull Mar Sci 26:41-48, 1976 11. Lopez A, Raibaut A: Multiple cutaneous fibromas in a mullet, Mugil cephalus cephalus L. J Fish Dis 4:169-174, 1981
12. Grizzle JM: Dermal fibroma in a redband parrotfish, Sparisoma aurofrenatum (Valenciennes). J Fish Dis 6:205-209, 1983 13. Manier JF, Raibaut A, Lopez A: A calcified fibroma in the common carp, Cyprinus carpio L. J Fish Dis 7:283-292, 1984 14. Constantino F, De Ocampo AA, García-Márquez LJ: Dermal fibroma in goldfish, Carassius auratus (L.). J Fish Dis 22:223-226, 1999 15. Honma Y: A case of the myxoma developed in the head of the salmonoid fish, the ayu Pleeoglossus altivelis Texnminck et Schlegel. Bull Jpn Soc Sci Fish 31:192-197, 1965 16. Keller M, Han S, Snekvik K: Severe anisakiasis and cutaneous myxoma in a California yellowtail, Seriola lalandi Valenciennes. J Fish Dis 34:635-639, 2011 17. Gjurčević E, Kužir S, Sfacteria A, et al: Spontaneous multicentric myxoma of the dermal nerve sheaths in farmed European eels Anguilla anguilla. Dis Aquat Organ 111:173-176, 2014 18. Singaravel V, Gopalakrishnan A, Vijayakumar R, et al: The case report on cutaneous myxoma or invasive myxomatosis in Blackfin sea catfish (Arius jella Day, 1877). Comp Clin Pathol 25:491-495, 2016 19. Walder EJ, Gross TL: Fibrocytic tumors, in Gross TL, Ihrke PJ, Walder EJ (eds):
Veterinary
Dermatopathology
A
Macroscopic
and
Microscopic
Evaluation of Canine and Feline Skin Disease. Mosby Year Book, St Louis, MO, pp 407-418, 1992 20. Chandra AMS, Buergelt CD, Ethell MT: Odontogenic myxoma of the mandible in a filly. J Vet Diagn Invest 11:274-277, 1999
21. Campbell MD, Gelberg HB: Endocardial ossifying myxoma of the right atrium in a cat. Vet Pathol 37:460-462, 2000 22. Berrocal A, Millan Y, Ordas J, et al: A joint myxoma in a dog. J Comp Pathol 124:223-226, 2001 23. Yeruham I, Perl S: Melanocytoma and myxoma-tumours of the limbs in cattle. Berl Munch Tierarztl Wochenschr 115:425-427, 2002 24. Oryan A, Ahmadi N, Ghane M, et al: Pulmonary myxoma in a sheep. J Comp Pathol 141: 187-189, 2009 25. Stoskopf MK: Fish medicine. W.B. Saunders, Mexico city, Mexico, 1993
FIGURE LEGENDS
FIGURE 1. Male flower horn fish (hybrid cichlid). Raised mass with umbilicated center on the head protuberance of male flower horn fish (arrows); Bar = 1 cm.
FIGURE 2. Male flower horn fish (hybrid cichlid). (A-H) Surgical wound healing after removing the mass within 40 days. Wound healing on surgery day (A), 1day (B), 3 days (C), 8 days (D), 18 days (E), 23 days (F), 28 days (G) and 40 days (H) after surgery. The remaining parts of the mass (arrowheads) were excised on day 9 post operatively.
FIGURE 3. Histological sections of fibromyxoma. (A) myxoid areas (*) and collagenous areas (arrows). H&E stain; Bar = 200 µm. (B) myxoid areas ( *) and collagenous areas (arrows). H&E stain; Bar = 100 µm. (C) Cytoplasmic extensions (arrows heads) of stellate myxoid cell (arrow) in a mucinous stroma. H&E stain; Bar = 20 µm. (D) Bizarre nucleus (arrow) of myxoid cell. H&E stain; Bar = 20 µm. (E) PAS positive cytoplasm of myxoid cells (arrows). PAS stain; Bar = 20 µm. (F) Masson’s trichrome positive of collagenous fibers. Masson’s trichrome stain; Bar = 20 µm.
Hooman
www.sasjournal.com
PII: DOI: Reference:
S1557-5063(17)30139-8 http://dx.doi.org/10.1053/j.jepm.2017.05.005 JEPM731
To appear in: Journal of Exotic Pet Medicine Cite this article as: Sara Shokrpoor, Farhang Sasani, Hooman Rahmati-Holasoo and Ashkan Zargar, FIBROMYXOMA IN A FLOWER HORN FISH (HYBRID CICHLID), Journal of Exotic Pet Medicine, http://dx.doi.org/10.1053/j.jepm.2017.05.005 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Case Report
Fibromyxoma in a Flower Horn Fish (Hybrid Cichlid) Sara Shokrpoor, DVM, DVSc, Farhang Sasani, DVM, DVSc, Hooman Rahmati-Holasoo, DVM, PhD Ashkan Zargar, DVM, PhD From the Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran (Shokrpoor, Sasani), Department of Aquatic Animal Health, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran (Rahmati-Holasoo, Zargar). Address correspondence to Sara Shokrapoor, DVM, DVSc, Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, P.O. Box 141556453, Tehran, Iran. E-mail address: [email protected]
Abstract A 3-year-old male flower horn fish with a mass on the head protuberance was referred to the Ornamental Fish Clinic, Faculty of Veterinary Medicine, University of Tehran. On gross examination, the mass was approximately 4×15×25 mm in size. The fish was anaesthetized in 100 ppm PI222 (Pars Imen Daru, Iran). The mass was removed surgically and the wound repair was post operatively monitored in the Ornamental Fish Clinic for 40 days. Tissue samples of the mass were fixed in 10% neutral buffered formalin, sectioned and stained with haematoxylin and eosin (H&E), Periodic Acid-Schiff (PAS) and
Masson’s
trichrome.
Microscopically,
as
a
consequence
of
the
concomitant presence of collagenous areas infiltrating myxoid areas, the neoplasm was classified as a fibromyxoma. Key words: Fibromyxoma; head protuberance; flower horn fish, neoplasm
A male flower horn fish (hybrid cichlid) with a mass on the head protuberance was referred to the Ornamental Fish Clinic, Faculty of Veterinary Medicine, University of Tehran (Fig. 1A). Based on owner information, the fish was 3-years-old and within the previous 6-month period of time the mass had become evident and grew larger. The flower horn fish’s behavior and appetite were considered normal. No parasite or ova were observed in wet smears of skin, gills, and feces. On gross examination, the fish measured 23 cm total length and the head mass was approximately 4×15×25 mm in size. The colored mass also exhibited an umbilicated center (Fig. 1). Water parameters were within normal range for this species of fish (29 °C, pH 7.2 and O2 7.9 mg/L) when the fish was first presented to the Ornamental Fish Clinic. The fish was anesthetized in 100 ppm PI222 (Pars Imen Daru, Iran) (PI222 is an herbal medicine and contains "eugenol, carvacrol, eugenol acetate and some other effective substances" as the active ingredients). The mass was surgically removed in a 5-minute procedure for diagnostic histopathological evaluation. During the surgical procedure the gills were periodically hydrated. Postoperatively, oxytetracycline (25 mg/kg, intramuscularly, Oxyvet®) was provided and then 10 mg/L oxytetracycline was added to the tank water and retreated on day 3 after 50% water change. After initially treatment, 50% of tank water was changed on days 6 and 9. Following the excision of the mass, the wound repair was monitored for 40 days in clinic (Fig. 2AH). The remaining parts of the mass (Fig. 2A,B,C) were excised completely on day 9 following the first surgical procedure. The fish was sedated each time the fish was photographed. The cut surface of the mass was soft with trabecular structures and gelatinous in consistency. Tissue samples of the mass were fixed in 10% neutral buffered formalin and routinely processed, dehydrated and embedded in paraffin wax, sectioned at 5 µm in thickness (Rotary Microtome RM2145; Leica) and stained
with hematoxylin and eosin (H&E). The mass sections were also stained with Periodic Acid-Schiff reaction (PAS) and Masson’s trichrome. Microscopically, the mass was capsulated and myxoid areas were characterized by stellate-to-reticular cells distributed in a mucinous stroma containing few tiny blood vessels that was partitioned by collagenous connective tissue septae (Fig. 3A,B,C). The myxoid cells were scattered appearing singly or in small clusters. There was no evidence of mitotic figures, but aberrant, bizarre and pyknotic nuclei were seen (Fig. 3D). The hypocellular mass showed neither hemorrhage nor necrosis. Myxoid cells displayed a PAS positive cytoplasm and round to oval, pale nuclei (Fig. 3E). The presence of stellate, reticular and PAS positive cells lying in a mucoid matrix are diagnostic of myxoma. Collagenous areas appeared rich in convoluted, collagenous fibers and in connective tissue cells, that included spindle-shaped fibroblast, in appearance, cells. Collagenous fibers stained also positive for Masson’s trichrome (Fig. 3F). Due to the concomitant presence of collagenous areas infiltrating myxoid areas, the neoplasm was classified as a fibromyxoma. Based on owner information, no new growth of the mass has been observed 8 months following the surgical procedures.
DISCUSSION The flower horn fish belongs to the Cichlid family. This species was believed to be a hybrid between the Midas cichlid (Amphilophus citrinellus) and three spot cichlid (Cichlasoma trimaculatum) which was first produced in Malaysia.1 It is also believed that this fish has emerged through selective cross-breeding of three spot cichlid (Cichlasoma trimaculatum), guayas cichlid (Cichlasoma festae) and Jingang Blood
Parrot (hybrid cichlid) in 1996.2,3,4,5 This fish is becoming increasingly popular as a pet, especially in South-East Asia and Iran.2,3,4,6 Fibromas are benign neoplasms of fibrocytes with abundant collagenous stroma. Myxomas are tumors of fibroblast origin distinguished by their abundant myxoid matrix, rich in mucopolysaccharides.7 The concomitant presence of collagenous areas delimiting and infiltrating myxoid areas lead the authors to classify the mass as a fibromyxoma.8 Fibromas have been described in electric catfish (Malapterurus electricus)9, southern flounder (Paralichthys lethostigma) and the hardhead sea catfish (Arius felis)10, flathead grey mullet (Mugil cephalus)11, redband parrotfish (Sparisoma aurofrenatum)12, common carp (Cyprinus carpio13, and goldfish (Carassius auratus)14. Myxomas have been reported in ayu sweetfish (Plecoglossus altivelis altivelis)15, yellowtail amberjack (Seriola lalandi)16, European eel (Anguilla anguilla)17, and Blackfin sea catfish (Arius jella)18. Fibromyxoma has rarely been diagnosed in fish only having been described in a tench (Tinca tinca)8. The presence of myxoid areas is a frequent occurrence in many mesenchymal neoplasms of domestic animals and humans.19 Myxomas have been reported in many species of animals including horses, cats, dogs, cattle and sheep.20,21,22,23,24 Myxomas have been also described in fish,15,16,17,18 but their occurrence is rare compared to fibromas.8 Microscopically, myxomas have low cellularity and rare mitoses, but increases in cellular density and mitoses warrant the diagnosis of myxosarcoma.7 However, no hypercellularity and mitoses were identified in the present case. Myxoma can be diagnosed only on the basis of tumor histopathology, because the loose tissue does not give clear and reliable
immunohistochemistry
results.17
The
intermediate
form
of
myxomas
(e.g.,
fibromyxoma) has been only reported in tench, Tinea tinea L.8 which had histological findings similar to the fibromyxoma diagnosed in the flower horn fish described in this report. Myxomas generally are considered to be spontaneous and self limiting16 and surgical excision is considered the treatment of choice for myxomas, fibromas, and intermediate forms7, which was also performed successfully in the present case. Fibromas and myxomas are usually diagnosed in adult or aged animals7 similar to fibromyxoma in the flower horn fish. Predisposing factors such as carcinogenic compounds, viruses, irritants, oncogenes, and parasites have all been reported in teleosts and should be considered potential sources for tumor induction in tropical fish.25 However in this report, no predisposing factors were observed and the underlying cause of the flower horn fish tumor remains unknown.
ACKNOWLEDGEMENTS Mr. Mehran Ahmadpour is thanked for assisting with the histopathological sections and figures.
REFERENCES 1. Shin SP, Jee H, Han JE, et al: Occurrence of Goiter in Flowerhorn Cichlid (Family: Cichlidae) and its Effect on Liver. J Vet clinic 27:202-204, 2010 2. Lin CC, Hung SW, Tu CY, et al: Spontaneous stomach lymphoma and liver metastases in flower horn fish, hybrid cichlid. Bull Eur Assoc Fish Pathol 28:115-120, 2008
3. Rahmati-Holasoo H, Hobbenaghi R, Tukmechi A, et al: Lymphocystis in a flower horn fish. Comp Clin Pathol 19:433-435, 2010 4. Rahmati-Holasoo H, Ebrahimzadeh Mousavi H, Vajhi A, et al: Polycystic liver in flower horn fish, hybrid cichlid. J Fish Dis 38:325-328, 2015a 5. Rahmati-Holasoo H, Masoudifard M, Ebrahimzadeh Mousavi H, et al: Cystic lesions in the kidney of flower horn fish, hybrid cichlid. J Fish Dis 38:833-838, 2015b 6. Rahmati-Holasoo H, Shokrpoor S, Tavakkoli A, et al: Liposarcoma or invasive lipomatosis in flower horn fish, hybrid cichlid: clinical, radiological, ultrasonographical and histopathological study. J Fish Dis 39:309-315, 2016 7. Goldschmidt MH, Hendrick MJ: Tumors of the skin and soft tissues, in Meuten DJ (ed): Tumors in Domestic Animals (ed 4). Ames, Iowa, Lawa State Press, pp 84-92, 2002 8. Manera M, Biavati S: A fibromyxoma in a tench, Tinca tinca L. J Fish Dis 18:627-630, 1995 9. Stolk A: Tumours of fishes. XIII. Multiple fibromas of the skin in the malapterurid Malapterurus electricus. Proc Kon Ned Akad Wetensch Ser C Biol Med Sci 60:41-52, 1957 10. Overstreet RM, Edwards RH: Mesenchymal tumors of some estuarine fishes of the northern Gulf of Mexico. II. Subcutaneous fibromas in the southern flounder, Paralichthys lethostigma, and the sea catfish, Arius felis. Bull Mar Sci 26:41-48, 1976 11. Lopez A, Raibaut A: Multiple cutaneous fibromas in a mullet, Mugil cephalus cephalus L. J Fish Dis 4:169-174, 1981
12. Grizzle JM: Dermal fibroma in a redband parrotfish, Sparisoma aurofrenatum (Valenciennes). J Fish Dis 6:205-209, 1983 13. Manier JF, Raibaut A, Lopez A: A calcified fibroma in the common carp, Cyprinus carpio L. J Fish Dis 7:283-292, 1984 14. Constantino F, De Ocampo AA, García-Márquez LJ: Dermal fibroma in goldfish, Carassius auratus (L.). J Fish Dis 22:223-226, 1999 15. Honma Y: A case of the myxoma developed in the head of the salmonoid fish, the ayu Pleeoglossus altivelis Texnminck et Schlegel. Bull Jpn Soc Sci Fish 31:192-197, 1965 16. Keller M, Han S, Snekvik K: Severe anisakiasis and cutaneous myxoma in a California yellowtail, Seriola lalandi Valenciennes. J Fish Dis 34:635-639, 2011 17. Gjurčević E, Kužir S, Sfacteria A, et al: Spontaneous multicentric myxoma of the dermal nerve sheaths in farmed European eels Anguilla anguilla. Dis Aquat Organ 111:173-176, 2014 18. Singaravel V, Gopalakrishnan A, Vijayakumar R, et al: The case report on cutaneous myxoma or invasive myxomatosis in Blackfin sea catfish (Arius jella Day, 1877). Comp Clin Pathol 25:491-495, 2016 19. Walder EJ, Gross TL: Fibrocytic tumors, in Gross TL, Ihrke PJ, Walder EJ (eds):
Veterinary
Dermatopathology
A
Macroscopic
and
Microscopic
Evaluation of Canine and Feline Skin Disease. Mosby Year Book, St Louis, MO, pp 407-418, 1992 20. Chandra AMS, Buergelt CD, Ethell MT: Odontogenic myxoma of the mandible in a filly. J Vet Diagn Invest 11:274-277, 1999
21. Campbell MD, Gelberg HB: Endocardial ossifying myxoma of the right atrium in a cat. Vet Pathol 37:460-462, 2000 22. Berrocal A, Millan Y, Ordas J, et al: A joint myxoma in a dog. J Comp Pathol 124:223-226, 2001 23. Yeruham I, Perl S: Melanocytoma and myxoma-tumours of the limbs in cattle. Berl Munch Tierarztl Wochenschr 115:425-427, 2002 24. Oryan A, Ahmadi N, Ghane M, et al: Pulmonary myxoma in a sheep. J Comp Pathol 141: 187-189, 2009 25. Stoskopf MK: Fish medicine. W.B. Saunders, Mexico city, Mexico, 1993
FIGURE LEGENDS
FIGURE 1. Male flower horn fish (hybrid cichlid). Raised mass with umbilicated center on the head protuberance of male flower horn fish (arrows); Bar = 1 cm.
FIGURE 2. Male flower horn fish (hybrid cichlid). (A-H) Surgical wound healing after removing the mass within 40 days. Wound healing on surgery day (A), 1day (B), 3 days (C), 8 days (D), 18 days (E), 23 days (F), 28 days (G) and 40 days (H) after surgery. The remaining parts of the mass (arrowheads) were excised on day 9 post operatively.
FIGURE 3. Histological sections of fibromyxoma. (A) myxoid areas (*) and collagenous areas (arrows). H&E stain; Bar = 200 µm. (B) myxoid areas ( *) and collagenous areas (arrows). H&E stain; Bar = 100 µm. (C) Cytoplasmic extensions (arrows heads) of stellate myxoid cell (arrow) in a mucinous stroma. H&E stain; Bar = 20 µm. (D) Bizarre nucleus (arrow) of myxoid cell. H&E stain; Bar = 20 µm. (E) PAS positive cytoplasm of myxoid cells (arrows). PAS stain; Bar = 20 µm. (F) Masson’s trichrome positive of collagenous fibers. Masson’s trichrome stain; Bar = 20 µm.