The growth pattern is distinctive: typically producing a concentric band of tumor nests interspersed among the muscle and stroma of the appendiceal wall extending up the shaft of the appendix. This makes the lesion difficult to suspect grossly and difficult to measure. Small tumor nests may be camouflaged amongst the muscle or in periappendiceal fat; cytokeratin preparations best demonstrate the tumor cells; mucin stains are also helpful in identifying them. They behave in a more aggressive manner than do classical appendiceal carcinoids. Spread is usually to regional lymph nodes, peritoneum, and particularly the ovary. They do not produce sufficient hormonal substances to cause carcinoid or other endocrine syndromes. In fact, they more closely resemble exocrine than endocrine tumors. The term crypt cell carcinoma has been used for them, and though perhaps more accurate than considering them carcinoids, has not been a successful competitor. Cause
Carcinoid syndrome involves multiple tumors in one out of five males. The incidence of gastric carcinoids is increased in achlorhydria, Hashimotos thyroiditis, and pernicious anemia. Treatment
Surgery, if feasible, is the only curative therapy. If the tumor has metastasized (most commonly, to the liver) and is considered incurable, there are some promising treatment modalities, such as radiolabeled octreotide (e.g. Lutetium (177Lu) DOTA-octreotate) or the radiopharmaceutical 131I-mIBG (meta iodo benzyl guanidine) for arresting the growth of the tumors and prolonging survival in patients with liver metastases, though these are currently experimental. Chemotherapy is of little benefit and is generally not indicated.
They conclude that ecotourism works best to conserve predators when the tourism industry is supported both politically and by the public, and when it is monitored and controlled at local, national, and international levels. Regulation and accreditation
Because the regulations of ecotourism may be poorly implemented, ecologically destructive greenwashed operations like underwater hotels, helicopter tours, and wildlife theme parks can be categorized as ecotourism along with canoeing, camping, photography, and wildlife observation. The failure to acknowledge responsible, low-impact ecotourism puts legitimate ecotourism companies at a competitive disadvantage. Management strategies to mitigate destructive operations include but are not limited to establishing a carrying capacity, site hardening, sustainable design, visitation quotas, fees, access restrictions, and visitor education. Many environmentalists have argued for a global standard that can be used for certification, differentiating ecotourism companies based on their level of environmental commitment, creating a standard to follow. A national or international regulatory board would enforce accreditation procedures, with representation from various groups including governments, hotels, tour operators, travel agents, guides, airlines, local authorities, conservation organizations, and non-governmental organizations. The decisions of the board would be sanctioned by governments, so that non-compliant companies would be legally required to disassociate themselves from the use of the ecotourism brand. In 1998, Crinion suggested a Green Stars System, based on criteria including a management plan, benefit for the local community, small group interaction, education value and staff training. Ecotourists who consider their choices would be confident of a genuine ecotourism experience when they see the higher star rating.