sidewise curvature of the spine), or other structural disfigurements that result from compensatory mechanisms. Presentation
FMC tumors most commonly present as slow-growing, firm, mobile, nontender, spindle-shaped masses in the lower two-thirds of the sternocleidomastoid muscle of infants within 8 weeks (average: 24 days) of delivery. At diagnosis, these infants heads may tilt toward the side with the mass while their chins tilt to the opposite, uninvolved side. This tilting is due to sternocleidomastoid muscle contracture. FMC tumors are more common in males and the right sternocleidomastoid muscle  although very rare cases present with bilateral tumors. Untreated, the masses may continue to grow for weeks after birth but then stabilize, start regressing after 4–8 months of life, and over the ensuing 1–2 years typically fully resolve. In three studies, >25%, >50% and >80% of these infants have had difficult deliveries such as a breech birth, delivery requiring forceps, primigravida birth (i.e. mothers first child), prolonged, difficult labor, or delivery by Caesarean section. From 6-20% of newborns with fibromatosis colli also present with other congenital lesions such as hip dysplasia or, less commonly, facial asymmetry. Pathology
Microscopic histopathological analyses of biopsied FMC tumor tissues typically find benign-appearing, spindle-shaped fibroblasts, decomposing skeletal muscle fibers, and, in some cases, regenerating skeletal muscle fibers in a collagen fiber-containing background. If necessary, these tumors are typically diagnosed by microscopic examination of fine-needle aspiration samples rather than the more invasive approach of tumor biopsy sampling. The asperates show scant to moderately cellular, scattered, oval-shaped to spindle-shaped fibroblasts, naked nuclei (i.e.
Polystyrene sulfonates are a group of medications used to treat high blood potassium. Effects generally take hours to days. They are also used to remove potassium, calcium, and sodium from solutions in technical applications. Common side effects include loss of appetite, gastrointestinal upset, constipation, and low blood calcium. These polymers are derived from polystyrene by the addition of sulfonate functional groups. Sodium polystyrene sulfonate was approved for medical use in the United States in 1958.A polystyrene sulfonate was developed in the 2000s to treat Clostridium difficile associated diarrhea under the name Tolevamer, but it was never marketed. Medical uses
Polystyrene sulfonate is usually supplied in either the sodium or calcium form. It is used as a potassium binder in acute and chronic kidney disease for people with hyperkalemia (abnormal high blood serum potassium levels). However, it is unclear if it is beneficial and there is concern about possible side effects when it is combined with sorbitol.Polystyrene sulfonates are given by mouth with a meal or rectally by retention enema. Side effects
Intestinal disturbances are common, including loss of appetite, nausea, vomiting, and constipation. In rare cases, it has been associated with colonic necrosis. Changes in electrolyte blood levels such as hypomagnesemia, hypocalcemia, and hypokalemia may occur. Polystyrene sulfonates should not be used in people with obstructive bowel disease and in newborns with reduced gut motility. Intestinal injury
A total of 58 cases of intestinal injury including necrosis of the colon have been reported with polystyrene sulfonate as of 2013.