Are there any circumstances where you recommend early institution of systemic therapy for patients with solitary plasmacytoma?  

Assuming a true solitary plasmacytoma with no bone marrow involvement, I do not recommend systemic therapy in almost all circumstances. However, there are times when the location of a solitary plasmacytoma precludes definitive/curative dose radiation; even with surgical resection, I would favor syst...

The only addendum I'll add to @Ben Derman's excellent response is that - while I personally don't request FISH analyses from bone biopsies (e.g., how SPs are diagnosed) - some centers do this routinely. The decalcification makes this tricky to do post hoc, so you have to plan in advance. If SP ...

Five to six percent of plasma cell neoplasms manifest themselves as solitary plasmacytomas. The risks:benefits do not support systemic treatment in a patient with a solitary plasmacytoma of the bone (SPB). If the bone marrow is positive for clonal plasma cells during work-up but is less than 10...