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\begin{document}

\title{SDHD Paraganglioma Presenting with Syncope}



\author[1]{David LaChance}%
\author[1]{Mohamed Shakir}%
\author[1]{Thanh Hoang}%
\affil[1]{Walter Reed National Military Medical Center}%


\vspace{-1em}



  
  \date{May 15, 2024}


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\selectlanguage{english}
\begin{abstract}
This is an atypical presentation of a rare diagnosis. It emphasizes the
need for thorough medical history, family history, physical examination
and workup. It also demonstrates how even nonfunctional paragangliomas
can cause mass effect leading to symptoms.%
\end{abstract}%



\sloppy


\par\null

\textbf{Disclaimer:} The views expressed in this article are those of
the authors and do not reflect the official policy of the Department of
Army/Navy/Air Force, Department of Defense, or the U.S. Government.

\textbf{Key Clinical Message:}

This is an atypical presentation of a rare diagnosis. It emphasizes the
need for thorough medical history, family history, physical examination
and workup. It also demonstrates how even nonfunctional paragangliomas
can cause mass effect leading to symptoms.

\textbf{Key words:}

SDHD, paraganglioma, pheochromocytoma, syncope

\textbf{Clinical vignette:}

A 29-year-old female presented after she lost consciousness and fell
while walking. Syncope was preceded by 15 minutes of flushing, nausea
and palpitations. She reports similar episodes in preceding months.
Assessment included normal vital signs, electrocardiogram,
echocardiogram, thyroid function, CBC, and CMP. Head/neck CT revealed
bilateral carotid body tumors (Fig 1). Her father has bilateral carotid
body tumors which were never evaluated. Plasma and urine metanephrines
were normal.

The carotid body tumor was excised. Pathology confirmed a paraganglioma
with positive synaptophysin (Fig 2a) and chromogranin (Fig 2b) stains.
Genetic testing revealed a succinate-dehydrogenase-complex subunit D
gene mutation, associated with hereditary paraganglioma-pheochromocytoma
(PGL/PCC) syndromes which commonly found in the carotid body. They
usually arise from the autonomic nervous system anywhere from the skull
base to the pelvis with an incidence of 1:30,000-1:100,000 (1). About
95\% of head and neck paragangliomas are non-secretory (2). Symptoms can
arise from catecholamine hypersecretion, presenting as hypertension,
headaches, diaphoresis, flushing, anxiety or palpitations, and can be
episodic or sustained, or mass effect. Treatment is resection of the
tumor(s) with alpha-adrenergic blockade pre-operatively, however
observation is reasonable for non-secretory, asymptomatic tumors.
Patients and first-degree relatives should be screened with biochemical
testing and imaging.



\textbf{Authors contribution statement:}

David LaChance, DO - Author

Mohamed K.M. Shakir, MD - reviewer

Thanh D. Hoang, DO -- reviewer and editor

\textbf{References:}

\begin{enumerate}
\tightlist
\item
  Potu KC, Pownell BR, Shaikh KA, Bhatia V. Carotid Body Paraganglioma
  With An SDHD Gene Mutation: The Need For Genetic Testing. AACE
  Clinical Case Rep. 2016;2(2):e91-95.
\item
  Else, Tobi. ``Hereditary Paraganglioma-Pheochromocytoma Syndromes.''
  GeneReviews\selectlanguage{ngerman}® {[}Internet{]}. U.S. National Library of Medicine, 4 Oct.
  2018, www.ncbi.nlm.nih.gov/books/NBK1548/.
\end{enumerate}

\textbf{Abbreviations:}

MRI: magnetic resonance imaging

CT: Computer tomography

SDHD: succinate dehydrogenase complex subunit D

PGL/PCC: paraganglioma-pheochromocytoma

CBC: complete blood count

CMP: comprehensive metabolic panel

\textbf{Figures Legend:}

Figure 1: Head/neck CT demonstrating bilateral masses in the carotid
bifurcations consistent with carotid body tumors

Figure 2a: Histology of excised paraganglioma showing positive
synaptophysin stain

Figure 2b: Histology of excised paraganglioma showing positive
chromogranin stain\selectlanguage{english}
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\includegraphics[width=0.70\columnwidth]{figures/Fig-2-a-paraganglioma-syn-mp/Fig-2-a-paraganglioma-syn-mp}

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