Mesenteric metastases from cutaneous malignant melanoma - Erler Zimmer 3D anatomy Series MP2083

This dissection model highlighting a Mesenteric Metastasis from Malignant Cutaneous Melanoma is part of the exclusive Monash 3D anatomy series, a comprehensive series of human dissections reproduced with ultra-high resolution color 3D printing.

Clinical History.

A 44-year-old man had a slowly growing skin lesion on his back. On presentation to the emergency department several years later, he complained of bone pain, hepatomegaly, and pleural effusion. He died shortly thereafter.

Pathology

The specimen is a loop of small intestine mounted to show the mesentery, which contains numerous small dark brown circumscribed nodules ranging from the size of a pinhead to about 1 cm in diameter. Histology confirmed the diagnosis of metastatic melanoma.

Further information

The most common form of melanoma is cutaneous melanoma, which develops from pigment-producing cells known as melanocytes. In women they occur most commonly on the legs, while in men they occur most commonly on the back. About 25 percent of melanomas develop from moles. Changes in a mole that may indicate melanoma include an increase in size, irregular borders, color change, itching or ulceration of the skin.

Cutaneous melanoma is associated with UV exposure to sunlight or tanning beds. Other risk factors for developing melanoma include fair complexion, presence of a large number of melanocytic nevi (moles), severe sunburn as a child, and immunosuppression. It accounts for about 5 percent of all skin cancer diagnoses but has the highest mortality rate of all skin cancers. Melanomas typically occur in sun-exposed areas as a pigmented lesion with irregular borders, variegated color, asymmetrical shape, and evolving over time.
There are multiple mutations common in melanoma. Loss of cell cycle control genes by mutation in CDKN2A genes. Mutations in pro-growth signaling pathways, such as BRAF and PI3K mutations, are frequently observed in melanomas as well as mutations that activate telomerase, such as the TERT gene. Recognition that melanoma antigens activate host immune responses has led to promising immunotherapy that improves host T-cell identification of these antigens.

The most common sites of melanoma metastasis are the lungs, liver, brain, and bone, as well as regional lymph nodes, and are highly dependent on the site of the primary tumor. Metastatic melanoma affecting the gastrointestinal tract may present with anemia, excessive bleeding, pain, obstruction or bowel invagination. The jejunum and ileum are the most commonly involved sites, followed by the colon, rectum, and stomach. Surgery has usually been reserved for patients with the above complications.
The likelihood of metastatic spread from cutaneous melanoma depends on the stage of the primary tumor, which is based on tumor depth, mitotic activity, and skin ulceration, as well as lymph node and solid organ involvement. The diagnosis of melanoma is made by excisional biopsy. Investigation for bone metastases is performed using blood tests (increased alkaline phosphatase, calcium, and LDH) and radiological investigations most commonly X-rays and CT scans, but MRI and PET scans may also be used. Treatment depends on the stage or tumor as well as the genetic and immune profiles of the melanoma. Treatment usually involves surgical resection, chemotherapy, targeted therapies (e.g., BRAF inhibitors), immunotherapy, radiation therapy, or most commonly a combination of treatments.

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What advantages does the Monash University anatomical dissection collection offer over plastic models or plastinated human specimens?

• Each body replica has been carefully created from selected patient X-ray data or human cadaver specimens selected by a highly trained team of anatomists at the Monash University Center for Human Anatomy Education to illustrate a range of clinically important areas of anatomy with a quality and fidelity that cannot be achieved with conventional anatomical models-this is real anatomy, not stylized anatomy.
• Each body replica has been rigorously checked by a team of highly trained anatomists at the Center for Human Anatomy Education, Monash University, to ensure the anatomical accuracy of the final product.
• The body replicas are not real human tissue and therefore not subject to any barriers of transportation, import, or use in educational facilities that do not hold an anatomy license. The Monash 3D Anatomy dissection series avoids these and other ethical issues that are raised when dealing with plastinated human remains.