Case Author(s): Ed Grishaw, M.D. and Barry A. Siegel, M.D. , 10/11/96 . Rating: #D3, #Q4

Diagnosis: Secretion of Tc-99m methylene diphosphonate (MDP) secondary to pedal hyperhidrosis

Brief history:

66-year-old woman with breast cancer, referred for bone scintigraphy to evaluate for metastatic disease.


Anterior and posterior whole body scintigrams.

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Full history/Diagnosis is available below

Diagnosis: Secretion of Tc-99m methylene diphosphonate (MDP) secondary to pedal hyperhidrosis

Full history:

66-year old woman with breast cancer and a long-standing history of pedal hyperhidrosis (of unknown etiology).


20.0 mCi of Tc-99m MDP i.v.


Initial delayed anterior and posterior images of the axial and appendicular skeleton demonstrate unusual radiopharmaceutical accumulation in the "soft tissues" of the feet, ankles, and lower calves in the distribution of the patient's stockings. A repeat anterior image after removal of the stockings demonstrates disappearance of most of the abnormal activity. Moderately intense abnormal tracer uptake persists within the left mid foot corresponding to degenerative changes demonstrated on plain radiographs (not provided). No evidence for skeletal metastatic disease is seen.


Radioactive contamination of the body surface or clothing may occur secondary to accidental spillage or secondary to excretion/secretion of tracer or its metabolites by the body. Differentiation from soft tissue uptake may be achieved by removing the patient's clothing, cleansing the contaminated area, and repeat imaging.

Hyperhidrosis occurs as either a generalized or localized phenomenon. Localized hyperhidrosis most frequently involves the palms, soles, and intertriginous areas (i.e., axillae, inguinal folds, and perineal areas). Most localized cases are secondary to emotional stimuli. Less common causes include tabes dorsalis, hemiplegia, and unilateral nerve disorders.

The mechanism for such substantial Tc-99m MDP secretion in sweat is unknown. Sweat contains trace quantities of phosphate, but significant concentrations of chloride. It is possible that Tc-99m MDP is secreted by sweat glands in a fashion similar to phoshphate ion. Alternatively, Tc-99m pertechnetate may be handled similar to chloride ion by the sweat glands, and this could be the radiochemical form of the tracer. Tc-99m pertechnetate excretion is felt to be unlikely in this patient because of the absence of activity within the salivary glands, thyroid, or stomach.

Case contributed by Paul Kountz, M.D., Redmond Regional Medical Center, Rome, GA

References: 1) Ajmani, et al. J Nucl Med 1976;18:801-802. 2) Domonkos. Andrews' Diseases of the Skin. Philadelphia, Saunders, 1971; pp 9-10. 3) Carruthers. Biochemistry of the Skin in Health and Disease. Springfield, Il, CC Thomas, 1962; pp 131-157.



Major teaching point(s):

See Discussion

Differential Diagnosis List

Urine contamination; venous occlusion secondary to tight stockings.

ACR Codes and Keywords:

References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Misc)

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Case number: bs065

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