Case of the week
What is your provisional diagnosis?
Okay, okay, potong steam I know but I have a biopsy set up (biopsy? biopsy of what??) and so I won't have answers for another few weeks. Some of you left pretty good answers. I had the patient bring in her cream to verify that she wasn't overdosing on topical Vit D for her psoriasis (she wasn't but that was on my radar too, good thoughts!). But I think the clue lies in her labs:
If her PTH is suppressed (telling us clearly this isn't mediated by parathyroid hormone), then the question I was asking myself is, what the heck is hydroxylating her 25-OH Vitamin D to 1,25-OH Vitamin D (which is usually mediated by PTH). And why the discordance between the low 25-OH D and the midnormal 1,25-OH D?
So, something is causing her to activate the Vit D leading to abnormal gut calcium absorption. Typically you think of granulomatous disease but you sometimes see this in hematological malignancies. I think that clue lies within the skin- while her extensor lesions look classical for psoriasis the trunk lesions do not. Indeed, cutaneous lymphoma has been reported to do precisely that. And when I google images for cutaneous lymphoma I got the picture above; almost a carbon copy of what my patient has.
So, I'm sending her for a skin biopsy to prove this (doesn't show up in blood studies, I was told when I shared my concerns with a hematologist). If it is, she should respond nicely to Prednisone.