Greg Lewbart


Hot Topic Article: An unusual cuticular tumor-like growth on the abdomen of a lobster, Homarus americanus.

October 24, 2013

Tags: Jeffrey D. Shields and Hamish J. Small. 2013. Journal of Invertebrate Pathology 114(3):245-149.

This interesting case report by two researchers from the Virginia Institute of Marine Science provides details of an unusual crustacean tumor called a hamartoma. This is the first reported case of such a neoplasm in a lobster and only the second crustacean hamartoma on record. The authors hypothesize that the tumor resulted from wound repair gone awry.


Tumors are rare in crustaceans, and whereas a few have been reported from the lobster Homarus americanus none have been adequately described. A lobster with an unusual, large, blue-colored tumor-like growth projecting laterally outward from the first abdominal somite was caught off Stonington, Maine, USA. The growth was rugose and covered by a relatively normal appearing cuticle with dispersed focal melanization. The underlying stroma consisted of an internal area of rescaffolded fibrous connective tissue, restructured muscle fibers, few arterioles, and an epidermal area comprised of columnar, highly vacuolated epithelial cells. No infectious pathogens or unusual inclusions were observed with microscopy and no eukaryotic pathogens were detected via molecular sequencing. Given the nature of the histology and the appearance of the growth, we identify the mass as a benign papilliform hamartoma that likely originated as a result of abnormal wound repair possibly initiated around ecdysis. This represents the first tumor-like hamartoma reported from a lobster, and the second hamartoma reported from a crustacean.

Selected Works

Science Writing
The Second Edition of Invertebrate Medicine was released in December, 2011. It has been substantially expanded from the first edition to reflect the tremendous growth of the pertinent literature and work that is being accomplished in the fields of invertebrate animal medicine, disease investigation, conservation, husbandry, and animal welfare. In 2012 it is being recognized with a Text and Academic Authors Association TEXTY award for excellence in the Life Sciences Category and first place in the Health Care Professionals (nonphysicians) category of the 2012 American Medical Writers Association Book Awards.
This book, edited by Karen L. Rosenthal, Neil A. Forbes, Frederic L. Frye, and Gregory A. Lewbart, utilizes approximately 400 clinical cases to describe and address many of the major medical and surgical conditions of exotic animal pets.
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Creative Non-Fiction
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....a darn good yarn.
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...well-told and environmentally informative story about buried treasure and smuggling of exotic animals...
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