abbreviation, hh/cm

Danish to English Medical Medical: Instruments prostate needle core biopsy

The context is the same as my last question, but the abbreviation is different.
They are both right at the bottom of the posting.

The text is the results of biopsies from the prostate.

A number of needle core biopsies were taken, and most were described like this:

Velegnet nålebiopsi fra prostata repræsenterende prostatavæv med bevaret lobulær opbygning. Fremtræder hyperplastisk, men der er ingen tegn på malignitet og heller ikke pågående inflammation.
...
Der er foretaget supplerende immunhistokemisk farvning for PIN, som viser manglende omgivende basalcellelag, hvorfor der er tale om et minimalt ca. 1 mm stort focus med højt differentieret primært adenokarcinom.

PIN = prostatic intraepithelial neoplasia

In the next section, under Makroskopi, the numbers vary, but the results are:

[01] 13 mm, a.i.
[02] 5 mm a.i.
...
...

[09] 12 mm a.i.
[10] 9 mm a.i. hh/cm

Thanks for any suggestions!