Table 2. Case reports detailing HER2-positive breast cancer PNDs.

Reference	HR/HER2 status	Histology	Stage	Antineuronal antibody present	PND syndrome
Olmez et al. [6]	HR+/HER2+	IDC	IIA	Anti-Ri	Opsoclonus
					Myoclonus
Le May et al. [7]	HR−/HER2+	IDC	IIB	Anti-Yo	PCD
Dalmau et al. [8]	HR−/HER2+	IDC	IIA	Anti-Yo	PCD
Diamanti et al. [9]	HR+/HER2+	IDC	IIIC	None	LMND
Ogita et al. [10]	HR−/HER2+	IDC	IIIC	Anti-Yo	PCD
Dorn et al. [11]	HR−/HER2+	IDC	IIIA	Anti-Yo	PCD
Rupasinghe and Butler [12]	Unknown HR/HER2+	Poorly differentiated adenocarcinoma	IIA	Anti-Yo	PCD
Frings et al. [13]	HR−/HER2+	ILC	IIIB	Anti-Yo	PCD
Sancho et al. [14]	HR+/HER2+	IDC	IIB	Anti-Yo	PCD

HER2 = human epidermal growth factor receptor 2; PND = paraneoplastic neurologic disorder; HR = hormone receptor; IDC = invasive ductal carcinoma; ILC = invasive lobular carcinoma; PCD = paraneoplastic cerebellar degeneration; LMND = lower motor neuron disease.